Fix modals to appear in fixed position, and ensure Android compat gets checked (#21279)

* Fix modals to appear in fixed position, and ensure Android compat gets checked

* No need to wrap this

static/js/zamboni/devhub.js

@@ -1365,7 +1365,14 @@ function initSubmitModals() {
           return false;
         }
         if (confirmedOnce) {
-          $input.prop('checked', !$input.prop('checked'));
+          setTimeout(function () {
+            // $().modal() calls preventDefault() before firing the callback
+            // but the checkbox is temporarily checked anyway when clicking on
+            // it (not the label). To work around this, we wrap our toggling
+            // in a setTimeout() to force it to wait for the event to be
+            // processed.
+            $input.prop('checked', !$input.prop('checked'));
+          }, 0);
         }
         return !confirmedOnce;
       },

static/js/zamboni/global.js

@@ -311,7 +311,7 @@ $.fn.modal = function (click_target, o) {
       top: toY + 'px',
       right: 'inherit',
       bottom: 'inherit',
-      position: 'absolute',
+      position: 'fixed',
     });
     return $modal;
   };