Use context parameter in models/git (#22367)

After #22362, we can feel free to use transactions without
`db.DefaultContext`.

And there are still lots of models using `db.DefaultContext`, I think we
should refactor them carefully and one by one.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

services/repository/files/commit.go

@@ -38,7 +38,7 @@ func CreateCommitStatus(ctx context.Context, repo *repo_model.Repository, creato
 	}
 	gitRepo.Close()
 
-	if err := git_model.NewCommitStatus(git_model.NewCommitStatusOptions{
+	if err := git_model.NewCommitStatus(ctx, git_model.NewCommitStatusOptions{
 		Repo:         repo,
 		Creator:      creator,
 		SHA:          sha,