Scoped labels: don't require holding alt key to remove (go-gitea#23303)

Alt doesn't work on all browsers, the simplest solution for v1.19 is to
just not require it and toggle the label by just clicking.

Part of go-gitea#22974

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

web_src/js/features/repo-legacy.js

@@ -145,19 +145,14 @@ export function initRepoCommentForm() {
 
       const clickedItem = $(this);
       const scope = $(this).attr('data-scope');
-      const canRemoveScope = e.altKey;
 
       $(this).parent().find('.item').each(function () {
         if (scope) {
           // Enable only clicked item for scoped labels
           if ($(this).attr('data-scope') !== scope) {
             return true;
           }
-          if ($(this).is(clickedItem)) {
-            if (!canRemoveScope && $(this).hasClass('checked')) {
-              return true;
-            }
-          } else if (!$(this).hasClass('checked')) {
+          if (!$(this).is(clickedItem) && !$(this).hasClass('checked')) {
             return true;
           }
         } else if (!$(this).is(clickedItem)) {