Handle a deletion of deployments for the removed repository

Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/398133

**Problem**

There is no verification in `#finalize_fast_destroy` if the repository
exists. Because of that, `#delete_refs` can raise an unhandled exception
and block the project destroy process.

**Solution**

Handle `Gitlab::Git::Repository::NoRepository` exception.

Changelog: fixed