Fix example/with-camera: Camera re-initialization and Layout fix

[mirsahib]

This PR introduces two key improvements to the camera functionality in with-camera/App.tsx:

1. Camera Re-initialization on Focus:

   • Change: Implemented useFocusEffect from expo-router to increment a cameraKey state variable whenever the screen gains focus. The CameraView component now uses this cameraKey as its key prop.
   • Purpose: This is an effective solution to ensure the CameraView component is re-mounted and re-initialized when the user navigates back to this screen. This addresses potential issues where the camera might not function correctly after being unfocused or backgrounded, providing a more robust user experience. The use of useCallback with useFocusEffect is also good practice for performance.

2. CameraView Children Limitation Fix:

   • Change: The CameraView component and its associated shutter controls (View component) are now wrapped within a React Fragment (<></>).
   • Purpose: This correctly addresses the limitation that CameraView does not support children. By making the CameraView and the controls siblings within a fragment, you can then use absolute positioning for the controls, ensuring they render correctly on top of the camera feed without causing inconsistent behavior or crashes.
   • Potential Fix

 WARN  The <CameraView> component does not support children. This may lead to inconsistent behaviour or crashes. If you want to render content on top of the Camera, consider using absolute positioning.