fix: apply library collection changes synchronously

to update the index before the frontend re-fetches

Author: pomegranited

openedx/core/djangoapps/content/search/handlers.py

@@ -167,10 +167,13 @@ def library_collection_updated_handler(**kwargs) -> None:
         log.error("Received null or incorrect data for event")
         return
 
-    update_library_collection_index_doc.delay(
+    # Update collection index synchronously to make sure that search index is updated before
+    # the frontend invalidates/refetches index.
+    # See content_library_updated_handler for more details.
+    update_library_collection_index_doc.apply(args=[
         str(library_collection.library_key),
         library_collection.collection_key,
-    )
+    ])
 
 
 @receiver(CONTENT_OBJECT_ASSOCIATIONS_CHANGED)