security: Prevent screenshots in private chat

[moehamade]

This commit adds a security feature that prevents recents automatic screen captures

Closes #595

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• Removed system recents screenshot on Android 13+

Checklist

• I have read the contribution guidelines: https://github.com/permissionlesstech/bitchat-android?tab=readme-ov-file#contributing
• I have performed a self-review of my code

• I have mentioned the corresponding issue and the relevant keyword (e.g., "Closes: #xy") in the description (see https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)
• If it is a core feature, I have added automated tests