fix d2-projects/d2-admin#248

Former-commit-id: 94b9d9f0679c5c82dd6f910a67937ad56e03a0e2

Author: FairyEver

src/store/modules/d2admin/modules/page.js

@@ -25,7 +25,7 @@ export default {
      * @param {Object} context
      */
     isLoaded ({ state }) {
-      if (state.value) return Promise.resolve()
+      if (state.openedLoaded) return Promise.resolve()
       return new Promise(resolve => {
         const timer = setInterval(() => {
           if (state.openedLoaded) {