[Bug]: build warning on Android for flatDir

### Capacitor Version

💊 Capacitor Doctor 💊

Latest Dependencies:

@capacitor/cli: 8.5.0
@capacitor/core: 8.5.0
@capacitor/android: 8.5.0
@capacitor/ios: 8.5.0

Installed Dependencies:

@capacitor/core: 8.5.0
@capacitor/cli: 8.5.0
@capacitor/android: 8.5.0
@capacitor/ios: 8.5.0

[success] iOS looking great! 👌
[success] Android looking great! 👌

### Other API Details

```Shell
npm: 11.13.0
node: v24.16.0
pod: 1.16.2
```

### Platforms Affected

- [ ] iOS
- [x] Android
- [ ] Web

### Current Behavior

There's a warning about flatDir which I think can be easily solved.

### Expected Behavior

No warning in the build

### Project Reproduction

Any new capacitor project

### Additional Information

You can find the two offending ones here:
https://github.com/search?q=repo%3Aionic-team%2Fcapacitor+flatdir&type=code)

They should be replaced with fileTree as far as I understand.

Start by examining the two flatDir occurrences identified in the linked Capacitor repository code search, along with their surrounding Android build configuration. Verify the appropriate fileTree replacement and check that a new Capacitor project builds without the flatDir warning.

Written by the indexing model from the issue text.