make sure we extend UmbApi

src/Umbraco.Web.UI.Client/src/packages/core/workspace/workspace-context/workspace-context.interface.ts

@@ -1,4 +1,6 @@
-export interface UmbWorkspaceContextInterface {
+import type { UmbApi } from '@umbraco-cms/backoffice/extension-api';
+
+export interface UmbWorkspaceContextInterface extends UmbApi {
 	readonly workspaceAlias: string;
 	// TODO: should we consider another name than entity type. File system files are not entities but still have this type.
 	getEntityType(): string;