Bump esbuild from 0.20.2 to 0.21.1 in /frontend

Bumps [esbuild](https://github.com/evanw/esbuild) from 0.20.2 to 0.21.1.
- [Release notes](https://github.com/evanw/esbuild/releases)
- [Changelog](https://github.com/evanw/esbuild/blob/main/CHANGELOG.md)
- [Commits](https://github.com/evanw/esbuild/compare/v0.20.2...v0.21.1)

---
updated-dependencies:
- dependency-name: esbuild
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

frontend/package.json

@@ -92,7 +92,7 @@
     "ngx-infinite-scroll": "^17.0.0",
     "qrcode": "1.5.1",
     "rxjs": "~7.8.1",
-    "esbuild": "^0.20.2",
+    "esbuild": "^0.21.1",
     "tinyify": "^4.0.0",
     "tlite": "^0.1.9",
     "tslib": "~2.6.0",