fix(h5): add a fake page instance to window component (question/146126)

packages/uni-h5/dist/uni-h5.cjs.js

@@ -7037,7 +7037,7 @@ function setupWindow(comp, id) {
       };
     },
     setup(instance) {
-      instance.root = instance;
+      instance.$pageInstance = instance;
     }
   });
 }

packages/uni-h5/dist/uni-h5.es.js

@@ -14260,7 +14260,7 @@ function setupWindow(comp, id2) {
       };
     },
     setup(instance2) {
-      instance2.root = instance2;
+      instance2.$pageInstance = instance2;
     }
   });
 }

packages/uni-h5/src/framework/setup/index.ts

@@ -72,7 +72,7 @@ export function setupWindow(comp: any, id: number) {
       } as Page.PageInstance['$page']
     },
     setup(instance) {
-      instance.root = instance // windows 中组件 root 指向 window
+      instance.$pageInstance = instance // window 的页面实例 $pageInstance 指向自己
     },
   })
 }