Fix margin for branch-update grid on PR view when update button is not present (#11521)

* Fix margin for branch-update grid on PR view when update button is not present

* Move padding to row element

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

web_src/less/_repository.less

@@ -648,13 +648,10 @@
                 }
                 .branch-update.grid {
                     .row {
-                        padding-bottom: 0;
+                        padding-bottom: 1rem;
                         .icon {
                             margin-top: 1.1rem;
                         }
-                        .ui.button {
-                            margin-bottom: 1rem;
-                        }
                     }
                 }
             }