Fix: iOS front camera switching crash issue

@@ -138,7 +138,7 @@ public class MobileScanner: NSObject, AVCaptureVideoDataOutputSampleBufferDelega
             if device.isFocusModeSupported(.continuousAutoFocus) {
                 device.focusMode = .continuousAutoFocus
             }
-            if #available(iOS 15.4, *) {
+            if #available(iOS 15.4, *) , device.isFocusModeSupported(.autoFocus){
                 device.automaticallyAdjustsFaceDrivenAutoFocusEnabled = false
             }
             device.unlockForConfiguration()