Initialize plugins for cli appbuilder (#30934)

Plugins can provide things that need to be initialized before we can use
the slim appbuilder for cli actions. For example, plugins can add menu items,
which need to be loaded for sync-perm to do everything it needs to do.

(cherry picked from commit 3560b92)

airflow/utils/cli_app_builder.py

@@ -24,12 +24,15 @@
 from flask import Flask
 
 from airflow.www.extensions.init_appbuilder import AirflowAppBuilder, init_appbuilder
+from airflow.www.extensions.init_views import init_plugins
 
 
 @lru_cache(maxsize=None)
 def _return_appbuilder(app: Flask) -> AirflowAppBuilder:
     """Returns an appbuilder instance for the given app"""
-    return init_appbuilder(app)
+    init_appbuilder(app)
+    init_plugins(app)
+    return app.appbuilder  # type: ignore[attr-defined]
 
 
 @contextmanager