Find LFS objects from fork instead of canonical project

As mentioned in #20042 (comment 260880716), we need to update all areas where Project#lfs_storage_project is called to reference the project itself (regardless if it's a fork or canonical project).

This should only be done once backfilling (#55487 (closed)) is finished and executed since at that point, necessary LfsObjectsProject records for existing forks will already be created and new records will be created.

Since forks have their own link to the LFS objects, we don't need to find LFS objects from the canonical project anymore.