project: run fetch --refetch on unable to not parse commit

Similarly to e59e2ae7, handle missing
gc'ed commits by running `git fetch --refetch`.

R=jojwang@google.com

Bug: b/360889369
Bug: b/371000949
Change-Id: I108b870b855d3b9f23665afa134c6e35f7cd2830
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/438461


Reviewed-by: Joanna Wang <jojwang@google.com>
Tested-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>