Create stub GraphQL API SetRepositoryPermissionsForBitbucketProject
Created by: indradhanush
Part 1 for #36454 (closed).
At the moment, the API doesn't really do anything apart from running some validation checks. Once we have the Bitbucket permissions worker implemented, this API will trigger a sync job and return a job ID or equivalent in the response instead of the currently empty response that it returns at the moment.
Test plan
Added new unit tests for the implemented functionality.