Synchronously store the revocation registry

[PatStLouis]

This is to address failing integration tests for revocation registry rotation:
https://github.com/openwallet-foundation/acapy/actions/runs/21226131058/job/61073454321?pr=4026

Some race conditions were causing the agent to try and set an active registry before it was stored locally.

[swcurran]

@ff137 -- don't know if you have time to look at this, but I know you have done a lot of work on revocation registry creation handling and errors. Your feedback would be appreciated.

[sonarqubecloud]

Quality Gate failed

Failed conditions
50.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud

[ff137]

LGTM!

create_and_register_revocation_registry_definition returns a RevRegDefResult | string, and if it was a string then it means it's an error message. The current logic:

        if new_reg:
            new_rev_reg_def_id = new_reg.rev_reg_def_id

would try to access .rev_reg_def_id on a string... which would raise an error. And that's my bad. I previously modified that and missed this.

So the change seems good and necessary to avoid that runtime error.

(A type checker like mypy would have caught this. Definitely worth it to try add mypy to this project, although it would require a lot of mini typing changes)