Disabling Bluetooth controllers also disables the Android Back input event

Disabling Bluetooth Controller support for Android also causes the Back button of the navigation bar to not work properly, as the input event does not fire when it is pressed.

Regression?: No
This didn't occur in 4.19 but the ability to disable Bluetooth Controller support (at least from the Project Settings) was not an option so this was unable to be tested.

1. Create a new project based off the Third Person Template
2. In the Third Person Character, add an Input event for the Android Back button and set it to do anything, such as quit the game
3. In Project Settings > Android > Input, disable Bluetooth controller support
4. Package the project for Android
5. Install/launch the app on an Android device (tested with Pixel XL)
6. Press back in attempt to fire the event
   Result: The event does not fire
   Expected: The event fires properly