npm-dep: bump prettier-plugin-tailwindcss in /frontend

Bumps [prettier-plugin-tailwindcss](https://github.com/tailwindlabs/prettier-plugin-tailwindcss) from 0.6.8 to 0.6.9.
- [Release notes](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/releases)
- [Changelog](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/compare/v0.6.8...v0.6.9)

---
updated-dependencies:
- dependency-name: prettier-plugin-tailwindcss
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

frontend/package.json

@@ -30,7 +30,7 @@
 		"postcss": "^8.4.49",
 		"prettier": "^3.3.3",
 		"prettier-plugin-svelte": "^3.2.8",
-		"prettier-plugin-tailwindcss": "^0.6.8",
+		"prettier-plugin-tailwindcss": "^0.6.9",
 		"svelte": "^4.2.19",
 		"svelte-check": "^4.0.9",
 		"tailwindcss": "^3.4.15",