Attract: Don't show add task button in cell if there are tasks

Requested by @fsiddi

src/scripts/js/es6/common/vuecomponents/attracttable/cells/renderer/CellTasks.js

@@ -30,9 +30,12 @@ let CellTasks = Vue.component('attract-cell-tasks', {
             return this.rawCellValue;
         },
         canAddTask() {
+            if (this.tasks.length < 1 ) {
                 let projectId = ProjectUtils.projectId();
                 return attract.auth.AttractAuth.canUserCreateTask(projectId);
             }
+            return false;
+        }
     },
     data() {
         return {