Update design-specific GH code-owners (#74877)

* Update design-specific GH code-owners

Created a `@elastic/stack-design` encompassing all product designers associated with the stack+solutions (Kibana repo contributors, not cloud). The `@elastic/kibana-design` team has been reduced to the actual Kibana design team. Then other individual design teams have been added as code-owners to their respective folders containing SASS changes.

.github/CODEOWNERS

@@ -8,6 +8,7 @@
 /x-pack/plugins/lens/ @elastic/kibana-app
 /x-pack/plugins/graph/ @elastic/kibana-app
 /src/plugins/dashboard/ @elastic/kibana-app
+/src/plugins/dashboard/**/*.scss @elastic/kibana-core-ui
 /src/plugins/discover/ @elastic/kibana-app
 /src/plugins/input_control_vis/ @elastic/kibana-app
 /src/plugins/kibana_legacy/ @elastic/kibana-app
@@ -58,6 +59,7 @@
 
 # APM
 /x-pack/plugins/apm/  @elastic/apm-ui
+/x-pack/plugins/apm/**/*.scss @elastic/observability-design
 /x-pack/test/functional/apps/apm/  @elastic/apm-ui
 /src/legacy/core_plugins/apm_oss/  @elastic/apm-ui
 /src/plugins/apm_oss/  @elastic/apm-ui
@@ -68,6 +70,7 @@
 
 # Canvas
 /x-pack/plugins/canvas/  @elastic/kibana-canvas
+/x-pack/plugins/canvas/**/*.scss @elastic/kibana-core-ui
 /x-pack/test/functional/apps/canvas/  @elastic/kibana-canvas
 
 # Core UI
@@ -77,15 +80,18 @@
 /src/plugins/home/server/services/ @elastic/kibana-core-ui
 # Exclude tutorial resources folder for now because they are not owned by Kibana app and most will move out soon
 /src/legacy/core_plugins/kibana/public/home/*.ts @elastic/kibana-core-ui
-/src/legacy/core_plugins/kibana/public/home/*.scss @elastic/kibana-core-ui
+/src/legacy/core_plugins/kibana/public/home/**/*.scss @elastic/kibana-core-ui
 /src/legacy/core_plugins/kibana/public/home/np_ready/ @elastic/kibana-core-ui
 
 # Observability UIs
 /x-pack/legacy/plugins/infra/ @elastic/logs-metrics-ui
 /x-pack/plugins/infra/ @elastic/logs-metrics-ui
+/x-pack/plugins/infra/**/*.scss @elastic/observability-design
 /x-pack/plugins/ingest_manager/ @elastic/ingest-management
+/x-pack/plugins/ingest_manager/**/*.scss @elastic/observability-design
 /x-pack/legacy/plugins/ingest_manager/ @elastic/ingest-management
 /x-pack/plugins/observability/ @elastic/observability-ui
+/x-pack/plugins/observability/**/*.scss @elastic/observability-design
 /x-pack/legacy/plugins/monitoring/ @elastic/stack-monitoring-ui
 /x-pack/plugins/monitoring/ @elastic/stack-monitoring-ui
 /x-pack/plugins/uptime @elastic/uptime
@@ -159,10 +165,14 @@
 # Security
 /src/core/server/csp/  @elastic/kibana-security @elastic/kibana-platform
 /x-pack/legacy/plugins/security/  @elastic/kibana-security
+/x-pack/legacy/plugins/security/**/*.scss @elastic/kibana-core-ui
 /x-pack/legacy/plugins/spaces/  @elastic/kibana-security
+/x-pack/legacy/plugins/spaces/**/*.scss @elastic/kibana-core-ui
 /x-pack/plugins/spaces/  @elastic/kibana-security
+/x-pack/plugins/spaces/**/*.scss @elastic/kibana-core-ui
 /x-pack/plugins/encrypted_saved_objects/  @elastic/kibana-security
 /x-pack/plugins/security/  @elastic/kibana-security
+/x-pack/plugins/security/**/*.scss @elastic/kibana-core-ui
 /x-pack/test/api_integration/apis/security/ @elastic/kibana-security
 
 # Kibana Localization
@@ -234,6 +244,7 @@ x-pack/plugins/telemetry_collection_xpack/schema/xpack_plugins.json @elastic/kib
 
 # Endpoint
 /x-pack/plugins/endpoint/ @elastic/endpoint-app-team @elastic/siem
+/x-pack/plugins/endpoint/**/*.scss @elastic/security-design
 /x-pack/test/api_integration/apis/endpoint/ @elastic/endpoint-app-team @elastic/siem
 /x-pack/test/endpoint_api_integration_no_ingest/ @elastic/endpoint-app-team @elastic/siem
 /x-pack/test/security_solution_endpoint/ @elastic/endpoint-app-team @elastic/siem
@@ -243,6 +254,7 @@ x-pack/plugins/telemetry_collection_xpack/schema/xpack_plugins.json @elastic/kib
 
 # Security Solution
 /x-pack/plugins/security_solution/ @elastic/siem @elastic/endpoint-app-team
+/x-pack/plugins/security_solution/**/*.scss @elastic/security-design
 /x-pack/test/detection_engine_api_integration @elastic/siem @elastic/endpoint-app-team
 /x-pack/test/api_integration/apis/security_solution @elastic/siem @elastic/endpoint-app-team
 /x-pack/plugins/case @elastic/siem @elastic/endpoint-app-team