fix(flow): excluding `packages/rn-tester/Pods/` from flow checks (#47474)

Summary:
When running the commands to check the flow types locally, there is quite some noise from files under `packages/rn-tester/Pods` that should not be checked as they are not from the source code itself.

<img width="839" alt="Screenshot 2024-11-07 at 00 50 55" src="https://github.com/user-attachments/assets/7ad3d96d-0f4a-4772-9e37-34d7e593b4cf">

## Changelog:

[INTERNAL] [FIXED] - Excluding `packages/rn-tester/Pods/` from flow checks

Pull Request resolved: https://github.com/facebook/react-native/pull/47474

Test Plan:
```bash
yarn flow
```

Reviewed By: cortinico

Differential Revision: D65594400

Pulled By: cipolleschi

fbshipit-source-id: d5e8828f41fc87c9a95293c250f24673ebbc6cd4