[server] Validate userID, teamID is a UUID on team operations

[easyCZ]

Description

To ensure we fail early on bogus values. This is also a necessary pre-cursor to use an authorization system as we need to guarantee consistency of records

Related Issue(s)

Fixes #

How to test

1. Interact with teams in preview
2. Make a request using the ws protocol with non-uuid values

Release Notes

NONE

Documentation

Werft options:

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-integration-tests=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh

[werft-gitpod-dev-com]

started the job as gitpod-build-mp-server-teams-rpc-validate-uuid.1 because the annotations in the pull request description changed
(with .werft/ from main)

[geropl]

I think there's nothing wrong with testing more invariants on the IDs per-se.
But I'd like to understand where it's coming from: Does OpenFGA expect UUIDs as data type? Does it perform other operations on it then "identity"? 🤔

[easyCZ]

Today, I can supply arbitrary strings to the RPCs and we'll happily go ahead and search for these in the database. Not only is it wasteful, but we also end up having a harder time figuring out why the system is doing it.

For any authorization system, the object and subject identifiers are strings. And that means we really want to be sure they are at least conforming to a valid pattern before we execute those queries.

But in general, we've gotta check our inputs, no matter what we use downstream.