Sync branches to DB immediately when handle git hook calling (gitea#29493)

Unlike other async processing in the queue, we should sync branches to
the DB immediately when handling git hook calling. If it fails, users
can see the error message in the output of the git command.

It can avoid potential inconsistency issues, and help #29494.

---------

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

models/git/branch.go

@@ -162,6 +162,11 @@ func GetBranch(ctx context.Context, repoID int64, branchName string) (*Branch, e
 	return &branch, nil
 }
 
+func GetBranches(ctx context.Context, repoID int64, branchNames []string) ([]*Branch, error) {
+	branches := make([]*Branch, 0, len(branchNames))
+	return branches, db.GetEngine(ctx).Where("repo_id=?", repoID).In("name", branchNames).Find(&branches)
+}
+
 func AddBranches(ctx context.Context, branches []*Branch) error {
 	for _, branch := range branches {
 		if _, err := db.GetEngine(ctx).Insert(branch); err != nil {