Extensions: Expose an enum for available placements (#64586)

* feat: expose an enum type for extension placements

* fix: export the enum properly

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

@@ -61,4 +61,5 @@ export {
   isPluginExtensionCommand,
   assertPluginExtensionCommand,
   PluginExtensionTypes,
+  PluginExtensionPlacements,
 } from './pluginExtensions';

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

@@ -2,6 +2,10 @@
  * These types are exposed when rendering extension points
  */
 
+export enum PluginExtensionPlacements {
+  DashboardPanelMenu = 'grafana/dashboard/panel/menu',
+}
+
 export enum PluginExtensionTypes {
   link = 'link',
   command = 'command',