chore(deps): update dependency angular-eslint to v21

Author: renovate[bot]

package.json

@@ -19,7 +19,7 @@
     "@angular/core": "21.0.0-rc.2",
     "@eslint/js": "^9.26.0",
     "@types/node": "^24.0.0",
-    "angular-eslint": "^20.0.0",
+    "angular-eslint": "^21.0.0",
     "eslint": "^9.26.0",
     "globals": "^16.1.0",
     "prettier": "~3.6.0",