[Serverless] Show project name in the header (#166442)

> [!IMPORTANT]  
> I plan to merge this as an intermediate state. The next step is
changing the breadcrumbs component and make the project name as part of
it #166593


## Summary

close #166182
Shows project name in the Kibana header. 
To test locally add to the `config/serverless.yml`: 

```
xpack.cloud.serverless.project_id: "random"
xpack.cloud.serverless.project_name: "My Search Project"
```

![Screenshot 2023-09-14 at 13 01
44](https://github.com/elastic/kibana/assets/7784120/4c658e19-5509-4a56-8752-a3a0f677d454)


I hardcoded 320px max-width to enable truncation for longer titles:
![Screenshot 2023-09-14 at 13 02
11](https://github.com/elastic/kibana/assets/7784120/4cab9643-3eb2-4d50-a737-66bb98a46109)

In general, the header is not very flexible and has issues on smaller
screen, but this needs to be fixed separately.


The link still leads to the `/projects` page of the cloud UI

packages/core/chrome/core-chrome-browser-internal/src/chrome_service.tsx

@@ -278,6 +278,11 @@ export class ChromeService {
       projectNavigation.setProjectsUrl(projectsUrl);
     };
 
+    const setProjectName = (projectName: string) => {
+      validateChromeStyle();
+      projectNavigation.setProjectName(projectName);
+    };
+
     const isIE = () => {
       const ua = window.navigator.userAgent;
       const msie = ua.indexOf('MSIE '); // IE 10 or older
@@ -371,6 +376,7 @@ export class ChromeService {
                 headerBanner$={headerBanner$.pipe(takeUntil(this.stop$))}
                 homeHref$={projectNavigation.getProjectHome$()}
                 projectsUrl$={projectNavigation.getProjectsUrl$()}
+                projectName$={projectNavigation.getProjectName$()}
                 docLinks={docLinks}
                 kibanaVersion={injectedMetadata.getKibanaVersion()}
                 prependBasePath={http.basePath.prepend}
@@ -499,6 +505,7 @@ export class ChromeService {
       project: {
         setHome: setProjectHome,
         setProjectsUrl,
+        setProjectName,
         setNavigation: setProjectNavigation,
         setSideNavComponent: setProjectSideNavComponent,
         setBreadcrumbs: setProjectBreadcrumbs,

packages/core/chrome/core-chrome-browser-internal/src/project_navigation/project_navigation_service.ts

@@ -46,6 +46,7 @@ export class ProjectNavigationService {
   }>({ current: null });
   private projectHome$ = new BehaviorSubject<string | undefined>(undefined);
   private projectsUrl$ = new BehaviorSubject<string | undefined>(undefined);
+  private projectName$ = new BehaviorSubject<string | undefined>(undefined);
   private projectNavigation$ = new BehaviorSubject<ChromeProjectNavigation | undefined>(undefined);
   private activeNodes$ = new BehaviorSubject<ChromeProjectNavigationNode[][]>([]);
   private projectNavigationNavTreeFlattened: Record<string, ChromeProjectNavigationNode> = {};
@@ -98,6 +99,12 @@ export class ProjectNavigationService {
       getProjectsUrl$: () => {
         return this.projectsUrl$.asObservable();
       },
+      setProjectName: (projectName: string) => {
+        this.projectName$.next(projectName);
+      },
+      getProjectName$: () => {
+        return this.projectName$.asObservable();
+      },
       setProjectNavigation: (projectNavigation: ChromeProjectNavigation) => {
         this.projectNavigation$.next(projectNavigation);
         this.projectNavigationNavTreeFlattened = flattenNav(projectNavigation.navigationTree);

packages/core/chrome/core-chrome-browser-internal/src/types.ts

@@ -50,6 +50,12 @@ export interface InternalChromeStart extends ChromeStart {
      */
     setProjectsUrl(projectsUrl: string): void;
 
+    /**
+     * Sets the project name.
+     * @param projectName
+     */
+    setProjectName(projectName: string): void;
+
     /**
      * Sets the project navigation config to be used for rendering project navigation.
      * It is used for default project sidenav, project breadcrumbs, tracking active deep link.

packages/core/chrome/core-chrome-browser-internal/src/ui/project/header.test.tsx

@@ -29,6 +29,7 @@ describe('Header', () => {
     helpMenuLinks$: Rx.of([]),
     homeHref$: Rx.of('app/home'),
     projectsUrl$: Rx.of('/projects/'),
+    projectName$: Rx.of('My Project'),
     kibanaVersion: '8.9',
     loadingCount$: Rx.of(0),
     navControlsLeft$: Rx.of([]),
@@ -82,5 +83,6 @@ describe('Header', () => {
 
     const projectsLink = await screen.getByTestId('projectsLink');
     expect(projectsLink).toHaveAttribute('href', '/projects/');
+    expect(projectsLink).toHaveTextContent('My Project');
   });
 });

packages/core/chrome/core-chrome-browser-internal/src/ui/project/header.tsx

@@ -73,6 +73,12 @@ const getHeaderCss = ({ size }: EuiThemeComputed) => ({
       padding-right: ${size.xs};
     `,
   },
+  projectName: {
+    link: css`
+      /* TODO: make header layout more flexible? */
+      max-width: 320px;
+    `,
+  },
 });
 
 type HeaderCss = ReturnType<typeof getHeaderCss>;
@@ -107,6 +113,7 @@ export interface Props {
   helpMenuLinks$: Observable<ChromeHelpMenuLink[]>;
   homeHref$: Observable<string | undefined>;
   projectsUrl$: Observable<string | undefined>;
+  projectName$: Observable<string | undefined>;
   kibanaVersion: string;
   application: InternalApplicationStart;
   loadingCount$: ReturnType<HttpStart['getLoadingCount$']>;
@@ -184,6 +191,7 @@ export const ProjectHeader = ({
   const toggleCollapsibleNavRef = createRef<HTMLButtonElement & { euiAnimate: () => void }>();
   const headerActionMenuMounter = useHeaderActionMenuMounter(observables.actionMenu$);
   const projectsUrl = useObservable(observables.projectsUrl$);
+  const projectName = useObservable(observables.projectName$);
   const { euiTheme } = useEuiTheme();
   const headerCss = getHeaderCss(euiTheme);
   const { logo: logoCss } = headerCss;
@@ -246,8 +254,12 @@ export const ProjectHeader = ({
               </EuiHeaderSectionItem>
 
               <EuiHeaderSectionItem>
-                <EuiHeaderLink href={projectsUrl} data-test-subj={'projectsLink'}>
-                  {headerStrings.cloud.linkToProjects}
+                <EuiHeaderLink
+                  href={projectsUrl}
+                  data-test-subj={'projectsLink'}
+                  css={headerCss.projectName.link}
+                >
+                  {projectName ?? headerStrings.cloud.linkToProjects}
                 </EuiHeaderLink>
               </EuiHeaderSectionItem>
 

packages/core/chrome/core-chrome-browser-mocks/src/chrome_service.mock.ts

@@ -70,6 +70,7 @@ const createStartContractMock = () => {
     project: {
       setHome: jest.fn(),
       setProjectsUrl: jest.fn(),
+      setProjectName: jest.fn(),
       setNavigation: jest.fn(),
       setSideNavComponent: jest.fn(),
       setBreadcrumbs: jest.fn(),

x-pack/plugins/serverless/public/plugin.tsx

@@ -68,6 +68,9 @@ export class ServerlessPlugin
     if (dependencies.cloud.projectsUrl) {
       project.setProjectsUrl(dependencies.cloud.projectsUrl);
     }
+    if (dependencies.cloud.serverless.projectName) {
+      project.setProjectName(dependencies.cloud.serverless.projectName);
+    }
 
     return {
       setSideNavComponent: (sideNavigationComponent) =>