[osquery] Remove unnecessary ghost colors from EuiBottomBar (#169309

)

## Summary

👋 Hey y'all - EUI will shortly be deprecating the `ghost` color in all
button components (see
https://eui.elastic.co/v89.0.0/#/navigation/button#ghost-vs-dark-mode).

In this PR, all components using `color="ghost"` are being used within
an `EuiBottomBar` and as such already automatically inherit dark mode
coloring.

I'm opening this PR ahead of time for your team so you can test this
migration and ensure no UI regressions have occurred as a result.

### Checklist

- [x] Tested in light and dark mode

x-pack/plugins/osquery/public/packs/form/index.tsx

@@ -300,7 +300,7 @@ const PackFormComponent: React.FC<PackFormProps> = ({
           <EuiFlexItem grow={false}>
             <EuiFlexGroup gutterSize="m">
               <EuiFlexItem grow={false}>
-                <EuiButtonEmpty color="ghost" {...cancelButtonProps}>
+                <EuiButtonEmpty color="text" {...cancelButtonProps}>
                   <FormattedMessage
                     id="xpack.osquery.pack.form.cancelButtonLabel"
                     defaultMessage="Cancel"

x-pack/plugins/osquery/public/routes/saved_queries/edit/form.tsx

@@ -67,7 +67,7 @@ const EditSavedQueryFormComponent: React.FC<EditSavedQueryFormProps> = ({
               <EuiFlexItem grow={false}>
                 <EuiFlexGroup gutterSize="m">
                   <EuiFlexItem grow={false}>
-                    <EuiButtonEmpty color="ghost" {...savedQueryListProps}>
+                    <EuiButtonEmpty color="text" {...savedQueryListProps}>
                       <FormattedMessage
                         id="xpack.osquery.editSavedQuery.form.cancelButtonLabel"
                         defaultMessage="Cancel"

x-pack/plugins/osquery/public/routes/saved_queries/new/form.tsx

@@ -60,7 +60,7 @@ const NewSavedQueryFormComponent: React.FC<NewSavedQueryFormProps> = ({
           <EuiFlexItem grow={false}>
             <EuiFlexGroup gutterSize="m">
               <EuiFlexItem grow={false}>
-                <EuiButtonEmpty color="ghost" {...savedQueryListProps}>
+                <EuiButtonEmpty color="text" {...savedQueryListProps}>
                   <FormattedMessage
                     id="xpack.osquery.addSavedQuery.form.cancelButtonLabel"
                     defaultMessage="Cancel"