Group Max Role validation

As part of the effort to improve the code owner validations we need to ensure groups that are assigned as code owners have a high enough max role assigned when they were invited to the project.

This is a continuation on from the new flow designed in Inaccessible Code Owner validation (#429261 - closed)

Status

This feature has been implemented behind a feature flag. Rollout can be tracked via [Feature flag] Rollout of `accessible_code_owne... (#524437 - closed)