fix(app-check): type def fixes

[MichaelVerdon]

Description

https://firebase.google.com/docs/reference/js/app-check.md#gettoken_39fc1b3

closes #8361

Related issues

Release Summary

Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
  • Yes
• My change supports the following platforms;
  • Android
  • iOS
  • Other (macOS, web)
• My change includes tests;
  • e2e tests added or updated in packages/\*\*/e2e
  • jest tests added or updated in packages/\*\*/__tests__
• I have updated TypeScript types that are affected by my change.
• This is a breaking change;
  • Yes
  • No

Test Plan

---

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Name	Status	Preview	Comments	Updated (UTC)
react-native-firebase	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Apr 14, 2025 1:45pm

[russellwheatley]

@MichaelVerdon - there are e2e tests failing because of the change to return type of getAppCheck() :https://github.com/invertase/react-native-firebase/actions/runs/13769712997/job/38560776497?pr=8367#step:16:14532

You also need to change these the way these are called:
https://github.com/invertase/react-native-firebase/blob/main/packages/app-check/lib/modular/index.js#L67
https://github.com/invertase/react-native-firebase/blob/main/packages/app-check/lib/modular/index.js#L77
https://github.com/invertase/react-native-firebase/blob/main/packages/app-check/lib/modular/index.js#L96

[mikehardy]

I pulled this locally for testing - and even after rebasing against current main, android and iOS appear to work fine for me, so it doesn't seem to have any functional issues. Code looks good on review, so LGTM for merge