Migrate project_authorizations to a linear query

As part of the investigation in Investigate growth in total_time for project_au... (#398261 - closed) it was identified that the project_authorization query, used in the AuthorizedProjectUpdate worker to correct any incomplete project access policies takes a significant amount of CPU time. The worker itself is needed as it's not trivial to remedy the cause of policy inconsistencies so we would aim to migrate the project_authorizations query to a linear one, and test for performance in production with a feature flag. This issue is to track that effort with a FF rollout #410459 (closed)