Enable to choose a camera device in UI

[samoylenkodmitry]

Summary by Sourcery

Introduce a feature in the UI to allow users to choose a camera device from a dropdown menu. Enhance the webcam_preview function to support camera selection by passing the selected camera index.

New Features:

• Add UI elements to allow users to select a camera device from a dropdown menu.

Enhancements:

• Modify the webcam_preview function to accept a camera index parameter, enabling the selection of different camera devices.