Bump @typescript-eslint/eslint-plugin from 6.10.0 to 6.21.0 in /webapp

Bumps [@typescript-eslint/eslint-plugin](https://github.com/typescript-eslint/typescript-eslint/tree/HEAD/packages/eslint-plugin) from 6.10.0 to 6.21.0.
- [Release notes](https://github.com/typescript-eslint/typescript-eslint/releases)
- [Changelog](https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/eslint-plugin/CHANGELOG.md)
- [Commits](https://github.com/typescript-eslint/typescript-eslint/commits/v6.21.0/packages/eslint-plugin)

---
updated-dependencies:
- dependency-name: "@typescript-eslint/eslint-plugin"
  dependency-version: 6.21.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

webapp/package.json

@@ -27,7 +27,7 @@
   "devDependencies": {
     "@types/react": "^18.2.37",
     "@types/react-dom": "^18.2.15",
-    "@typescript-eslint/eslint-plugin": "^6.10.0",
+    "@typescript-eslint/eslint-plugin": "^6.21.0",
     "@typescript-eslint/parser": "^6.10.0",
     "@vitejs/plugin-react": "^4.7.0",
     "eslint": "^8.53.0",