FS: Remove multiTenantFrontend flag (#110776)

* FS: Move multiTenantFrontend evaluation to OpenFeature

* comment

* actually, just remove the toggle

* fix k8s prefs test using toggle

* replace frontend flag usage

* codeowners

* move isFrontendService just into core

* put back comment

packages/grafana-data/src/types/config.ts

@@ -195,6 +195,9 @@ export interface BootData {
     light: string;
     dark: string;
   };
+
+  /** @deprecated Internal Grafana usage only. This property will be removed at any time. */
+  _femt?: boolean;
 }
 
 /**

packages/grafana-data/src/types/featureToggles.gen.ts

@@ -965,10 +965,6 @@ export interface FeatureToggles {
   */
   pluginsAutoUpdate?: boolean;
   /**
-  * Register MT frontend
-  */
-  multiTenantFrontend?: boolean;
-  /**
   * Enables the alerting list view v2 preview toggle
   */
   alertingListViewV2PreviewToggle?: boolean;