Bump @docusaurus/plugin-google-gtag from 3.9.0 to 3.9.1 in /docs

Bumps [@docusaurus/plugin-google-gtag](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus-plugin-google-gtag) from 3.9.0 to 3.9.1.
- [Release notes](https://github.com/facebook/docusaurus/releases)
- [Changelog](https://github.com/facebook/docusaurus/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/docusaurus/commits/v3.9.1/packages/docusaurus-plugin-google-gtag)

---
updated-dependencies:
- dependency-name: "@docusaurus/plugin-google-gtag"
  dependency-version: 3.9.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

docs/package.json

@@ -16,7 +16,7 @@
     "dependencies": {
         "@docsearch/js": "^4.1.0",
         "@docusaurus/core": "^3.9.0",
-        "@docusaurus/plugin-google-gtag": "^3.8.1",
+        "@docusaurus/plugin-google-gtag": "^3.9.1",
         "@docusaurus/preset-classic": "^3.9.0",
         "@docusaurus/theme-mermaid": "^3.9.0",
         "@iconify/react": "^6.0.2",