docker repos synced to capsule do not use a proper repo_registry_id on initial sync
If you create a docker repository, and then sync it to the capsule (in a cv or not), then list the pulp distributor for that docker repo on the capsule, you will not see the 'repo_registry_id' set in pulp.
If you re-sync the capsule, it will show up properly
Fixes #21397 - set repo_registry_id on initial smart proxy sync
for docker repos