chore(deps): bump eslint-config-next from 13.5.2 to 15.1.5 in /frontend

Bumps [eslint-config-next](https://github.com/vercel/next.js/tree/HEAD/packages/eslint-config-next) from 13.5.2 to 15.1.5.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/commits/v15.1.5/packages/eslint-config-next)

---
updated-dependencies:
- dependency-name: eslint-config-next
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

frontend/package.json

@@ -37,7 +37,7 @@
     "cosmjs-types": "^0.9.0",
     "date-fns": "2.30.0",
     "eslint": "8.50.0",
-    "eslint-config-next": "13.5.2",
+    "eslint-config-next": "15.1.5",
     "fast-average-color": "^9.4.0",
     "jsonschema": "^1.4.1",
     "lodash": "^4.17.21",