fix inconsistencies when user switches camera mode fast

- debounce switching by 500ms when toggling between video/photo capture
- ensure there is only one source of truth for the current camera mode - this is the CameraXPreview
- refactor the MainActivity to depend on the CameraXPreview for the camera mode
- remove unused code in CameraXPreviewListener, MyPreview and in MainActivity

app/src/main/kotlin/com/simplemobiletools/camera/implementations/CameraXInitializer.kt

@@ -23,7 +23,8 @@ class CameraXInitializer(private val activity: BaseSimpleActivity) {
             mediaOutputHelper,
             cameraErrorHandler,
             listener,
-            initInPhotoMode,
+            isThirdPartyIntent = isThirdPartyIntent,
+            initInPhotoMode = initInPhotoMode,
         )
     }