Fix mounted event after initial hydration (#3480)

* trigger queued mounted events immediately after hydrating

* add a playwright test to prevent regressions

packages/playwright-tests/playwright.config.js

@@ -102,6 +102,15 @@ module.exports = defineConfig({
       reuseExistingServer: !process.env.CI,
       stdout: "pipe",
     },
+    {
+      cwd: path.join(process.cwd(), "fullstack-mounted"),
+      command:
+        'cargo run --package dioxus-cli --release -- serve --force-sequential --platform web --addr "127.0.0.1" --port 7777',
+      port: 7777,
+      timeout: 50 * 60 * 1000,
+      reuseExistingServer: !process.env.CI,
+      stdout: "pipe",
+    },
     {
       cwd: path.join(process.cwd(), "suspense-carousel"),
       command: