Add missing get_full_path import in registry_api

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dralley

pulp_container/app/registry_api.py

@@ -81,6 +81,7 @@
     determine_media_type,
     extract_data_from_signature,
     filter_resource,
+    get_full_path,
     has_task_completed,
     validate_manifest,
 )