Fix saving a comment multiple times (#6054)

[ci skip]

frontend/app/components/work-packages/work-package-comment/work-package-comment.directive.ts

@@ -104,7 +104,7 @@ export class CommentFieldDirectiveController {
   }
 
   public handleUserSubmit() {
-    if (this.field.isEmpty()) {
+    if (this.field.isBusy || this.field.isEmpty()) {
       return;
     }
 

frontend/app/components/wp-edit/field-controls/wp-edit-field-controls.directive.html

@@ -2,7 +2,7 @@
   <div class="inplace-edit--controls"
        ng-hide="!vm.fieldController.active">
     <accessible-by-keyboard execute="vm.onSave()"
-                            ng-disabled="vm.field.required && vm.field.isEmpty()"
+                            ng-disabled="vm.field.isBusy || (vm.field.required && vm.field.isEmpty())"
                             is-disabled="vm.field.required && vm.field.isEmpty()"
                             link-title="{{ vm.saveTitle }}"
                             class="inplace-edit--control inplace-edit--control--save">