Add Camera Access Check to AI Attendance Program

[Chinmayjod12]

This pull request introduces a camera access verification feature in the AI Attendance Program. The following changes have been made:

Camera Accessibility Check: Added a check to verify if the webcam is successfully opened. If the camera cannot be accessed, an error message is displayed, and the program exits gracefully. Error Handling: Implemented error handling to ensure that the application provides feedback in case the camera is not accessible or fails to read the input frame.