fix(vue2): get Vue from global hook

packages/app-backend-core/src/app.ts

@@ -12,6 +12,7 @@ import { JobQueue } from './util/queue'
 import { scan } from './legacy/scan'
 import { addBuiltinLayers, removeLayersForApp } from './timeline'
 import { getBackend, availableBackends } from './backend'
+import { hook } from './global-hook.js'
 
 const jobs = new JobQueue()
 
@@ -30,6 +31,10 @@ async function registerAppJob (options: AppRecordOptions, ctx: BackendContext) {
     return
   }
 
+  if (!options.version) {
+    throw new Error('[Vue Devtools] Vue version not found')
+  }
+
   // Find correct backend
   const baseFrameworkVersion = parseInt(options.version.substring(0, options.version.indexOf('.')))
   for (let i = 0; i < availableBackends.length; i++) {
@@ -221,16 +226,6 @@ export async function removeApp (app: App, ctx: BackendContext) {
   }
 }
 
-// eslint-disable-next-line camelcase
-function _legacy_getVueFromApp (app) {
-  if (app.constructor.name === 'VueComponent') {
-    // When Vue.extend is used the component is an instance of VueComponent instead of Vue.
-    // VueComponent has a property super which points to the original Vue constructor
-    return app.constructor.super
-  }
-  return app.constructor
-}
-
 // eslint-disable-next-line camelcase
 export async function _legacy_getAndRegisterApps (ctx: BackendContext) {
   // Remove apps that are legacy
@@ -242,11 +237,11 @@ export async function _legacy_getAndRegisterApps (ctx: BackendContext) {
 
   const apps = scan()
   apps.forEach(app => {
-    const Vue = _legacy_getVueFromApp(app)
+    const Vue = hook.Vue
     registerApp({
       app,
       types: {},
-      version: Vue.version,
+      version: Vue?.version,
       meta: {
         Vue,
       },