Backport #29288 Partially fix #29071, regression of Modernize merge button #28140 Fix some missing `Redirect` -> `JSONRedirect`. Thanks @yp05327 for the help in https://github.com/go-gitea/gitea/issues/29071#issuecomment-1931261075 (cherry picked from commit dcb9c38568dc4e9502fc416de237cce0eac41cba)