[git] Find the actual commit annotated tags refer to instead of the tag object.

There is a bug in the git module handling of git tags. When the git module version parameter is an annotated tag (all github tags are annotated), the git module incorrectly gets the tag object id instead of the commit it points to in get_remote_head(). This bug results in check mode always reporting a task as changed and unnecessary work in real runs.

The proposed change fixes the bug by always finding the dereferenced tag from ls-remote for annotated tags.