[iPad OS] The camera fails to initialize when the app is running in Split View or Slide Over mode on iPad.

**Is your feature request related to a problem? Please describe.**
I’m using the Agora Flutter SDK to build a video call app on iOS.
When the app runs in Split View or Slide Over mode on iPad, the camera cannot be started. This is likely due to the missing isMultitaskingCameraAccessEnabled = true setting on the underlying AVCaptureSession.

**Describe the solution you'd like**
It would be helpful to have a method exposed in the Flutter SDK to enable isMultitaskingCameraAccessEnabled on iOS, or ensure it is enabled by default in supported environments.

**Describe alternatives you've considered**

**Additional context**

agora 6.5.1
iPad Gen 10