borg backup: do not backup remote content by default

group_vars/matrix_servers

@@ -3144,7 +3144,7 @@ backup_borg_location_source_directories:
 
 backup_borg_location_exclude_patterns: |
   {{
-    ([matrix_synapse_media_store_path + '/local_thumbnails', matrix_synapse_media_store_path + '/remote_thumbnail', matrix_synapse_media_store_path + '/url_cache', matrix_synapse_media_store_path + '/url_cache_thumbnails'] if matrix_homeserver_implementation == 'synapse' else [])
+    ([matrix_synapse_media_store_path + '/remote_content', matrix_synapse_media_store_path + '/local_thumbnails', matrix_synapse_media_store_path + '/remote_thumbnail', matrix_synapse_media_store_path + '/url_cache', matrix_synapse_media_store_path + '/url_cache_thumbnails'] if matrix_homeserver_implementation == 'synapse' else [])
     +
     ([postgres_data_path] if postgres_enabled else [])
   }}