Migrate RNTester to use `{usesCleartextTraffic}` Manifest Placeholder (#52620)

Summary:
This creates a `debugOptimized` build type for React Native Android, meaning that we can run C++ optimization on the debug build, while still having the debugger enabled. This is aimed at improving the developer experience for folks developing on low-end devices or emulators.

Users that intend to debug can still use the `debug` variant where the full debug symbols are shipped.

## Changelog:

[ANDROID] [ADDED] - Create a debugOptimized buildType for Android

Pull Request resolved: https://github.com/facebook/react-native/pull/52620

Test Plan:
Tested locally with RNTester by doing:

```
./gradlew installDebugOptimized
```

This is the output of the 3 generated .aar. The size difference is a proof that we're correctly stripping out the C++ debug symbols:

<img width="193" height="54" alt="Screenshot 2025-07-15 at 17 49 50" src="https://github.com/user-attachments/assets/584a0e8d-2d17-40d4-ac29-da09049d6554" />
<img width="235" height="51" alt="Screenshot 2025-07-15 at 17 49 39" src="https://github.com/user-attachments/assets/eda8f9e7-3509-4334-8c16-990e55caa04d" />
<img width="184" height="52" alt="Screenshot 2025-07-15 at 17 49 32" src="https://github.com/user-attachments/assets/a5c94385-bc00-4484-b43e-088ee039827f" />

Rollback Plan:

Reviewed By: cipolleschi

Differential Revision: D78351347

Pulled By: cortinico

fbshipit-source-id: 568a484ba8d2ee6e089cabc95451938e853fbc54