chore: bump postcss from 8.4.41 to 8.4.43 in /frontend/extension (#294)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.41 to 8.4.43.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.4.41...8.4.43)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

frontend/extension/package.json

@@ -35,7 +35,7 @@
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-prettier": "^5.2.1",
     "eslint-plugin-react": "^7.35.0",
-    "postcss": "^8.4.41",
+    "postcss": "^8.4.43",
     "prettier": "^3.3.3",
     "tailwindcss": "^3.4.10",
     "typescript": "^5.5.4"