[Bug] 🐛 Public agent endpoint is not updated

When the public agent endpoint, which gets registered on the ledger, is updated and Traction restarted ALL tenants having recorded a public DID and their endpoint should automatically update the value by creating a newer `ATTRIB` transaction with the new endpoint. This does not seem to be working, and the old endpoint remains in place.

This may be in ACA-Py multitenancy and not Traction, but it is worth starting the investigation from here.

Start in Traction's public-agent endpoint registration and ACA-Py multitenancy flow, then reproduce a restart with tenants that have recorded public DIDs. Done means each affected tenant has a newer ATTRIB transaction containing the updated endpoint and the old endpoint is no longer retained.

Written by the indexing model from the issue text.