Updating OIDC scope of AuthMethod fails silently

[tgross]

While working on testing #19318 I discovered that updating the OIDCScope field of a AuthMethod via nomad acl auth-method update doesn't appear to update the scopes. I took a very quick look through the code and didn't see any obvious reason for it, but the way we update hashes in the RPC handler looks suspicious to me. I'll follow-up with more.

[github-actions]

I'm going to lock this issue because it has been closed for 120 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.