Bump undici, @react-native-firebase/app and @react-native-firebase/auth

Bumps [undici](https://github.com/nodejs/undici) to 6.21.1 and updates ancestor dependencies [undici](https://github.com/nodejs/undici), [@react-native-firebase/app](https://github.com/invertase/react-native-firebase) and [@react-native-firebase/auth](https://github.com/invertase/react-native-firebase). These dependencies need to be updated together.


Updates `undici` from 6.19.7 to 6.21.1
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v6.19.7...v6.21.1)

Updates `@react-native-firebase/app` from 21.7.1 to 21.7.1
- [Release notes](https://github.com/invertase/react-native-firebase/releases)
- [Changelog](https://github.com/invertase/react-native-firebase/blob/main/CHANGELOG.md)
- [Commits](invertase/react-native-firebase@v21.7.1...v21.7.1)

Updates `@react-native-firebase/auth` from 21.7.1 to 21.7.1
- [Release notes](https://github.com/invertase/react-native-firebase/releases)
- [Changelog](https://github.com/invertase/react-native-firebase/blob/main/CHANGELOG.md)
- [Commits](invertase/react-native-firebase@v21.7.1...v21.7.1)

---
updated-dependencies:
- dependency-name: undici
  dependency-type: indirect
- dependency-name: "@react-native-firebase/app"
  dependency-type: direct:production
- dependency-name: "@react-native-firebase/auth"
  dependency-type: direct:production
...

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

Author: dependabot[bot]

package.json

@@ -23,8 +23,8 @@
     "@dev-plugins/react-navigation": "^0.1.0",
     "@expo/vector-icons": "^14.0.4",
     "@react-native-async-storage/root": "github:react-native-async-storage/async-storage",
-    "@react-native-firebase/app": "^21.6.2",
-    "@react-native-firebase/auth": "^21.6.2",
+    "@react-native-firebase/app": "^21.7.1",
+    "@react-native-firebase/auth": "^21.7.1",
     "@react-native-firebase/messaging": "^21.7.1",
     "@react-navigation/native": "^7.0.0",
     "@react-navigation/native-stack": "^7.0.0",