Add Offline Caching Support for Conversations in React Native UI Kit

n CometChat React Native UI Kit, the Conversations and Chat components re-render/reinitialize every time the screen regains focus, causing UI lag and brief freezes.

A built-in offline caching mechanism is needed to persist conversations and messages locally, so the UI can reuse existing data instead of rebuilding on each navigation.

This would ensure smoother transitions, reduce unnecessary re-renders, and enable incremental updates instead of full reloads.