Convert delete_url_cache_media to async/await. (matrix-org#7241)

Author: clokep

changelog.d/7241.misc

@@ -0,0 +1 @@
+Convert some of synapse.rest.media to async/await.

synapse/storage/data_stores/main/media_repository.py

@@ -367,7 +367,7 @@ def _get_url_cache_media_before_txn(txn):
             "get_url_cache_media_before", _get_url_cache_media_before_txn
         )
 
-    def delete_url_cache_media(self, media_ids):
+    async def delete_url_cache_media(self, media_ids):
         if len(media_ids) == 0:
             return
 
@@ -380,6 +380,6 @@ def _delete_url_cache_media_txn(txn):
 
             txn.executemany(sql, [(media_id,) for media_id in media_ids])
 
-        return self.db.runInteraction(
+        return await self.db.runInteraction(
             "delete_url_cache_media", _delete_url_cache_media_txn
         )