feat: reactive channel preview data state

[isekovanic]

🎯 Goal

This PR moves the channel preview data state to use our reactive store rather than handle it implicitly within the SDK (for V10).

This:

• Removes a significant amount of WS event listeners
• Fixes a bunch of edge cases which were not possible to fix before
• Removes reliance on the local unreads custom event as well as this is now handled in the store

🛠 Implementation details

🎨 UI Changes

iOS

Before	After

Android

Before	After

🧪 Testing

☑️ Checklist

• I have signed the Stream CLA (required)
• PR targets the develop branch
• Documentation is updated
• New code is tested in main example apps, including all possible scenarios
  • SampleApp iOS and Android
  • Expo iOS and Android