Fix hydration with empty spread attributes (#4647)

* Fix hydration of empty spread attributes

* add a regression test

* fix doctest

packages/playwright-tests/playwright.config.js

@@ -108,6 +108,15 @@ module.exports = defineConfig({
       reuseExistingServer: !process.env.CI,
       stdout: "pipe",
     },
+    {
+      cwd: path.join(process.cwd(), "fullstack-spread"),
+      command:
+        'cargo run --package dioxus-cli --release -- run --verbose --force-sequential --web --addr "127.0.0.1" --port 7979',
+      port: 7979,
+      timeout: 50 * 60 * 1000,
+      reuseExistingServer: !process.env.CI,
+      stdout: "pipe",
+    },
     {
       cwd: path.join(process.cwd(), "fullstack-routing"),
       command: