Previously LFS uploads would always have to be reuploaded to a fork even
if the parent already had received the LFS file, but this is
unnecessary, wasting time and bandwidth. Consider this sequence of
events:

1. Push LFS file `test.bin` to project A.
2. Fork project A to project B.
3. Push LFS file `test2.bin` to project A.
4. Push to project B.

When 4 happens, GitLab should be smart enough to realize that if the
user has access to the parent project, then we should be able to link
the LFS files in A without requesting a reupload of the file.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/297022

Changelog: fixed