refactor some functions to support ctx as first parameter (#21878)

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
Co-authored-by: Lauris BH <lauris@nix.lv>

services/pull/update.go

@@ -99,7 +99,7 @@ func IsUserAllowedToUpdate(ctx context.Context, pull *issues_model.PullRequest,
 		BaseBranch: pull.HeadBranch,
 	}
 
-	err = pr.LoadProtectedBranch()
+	err = pr.LoadProtectedBranch(ctx)
 	if err != nil {
 		return false, false, err
 	}