Enhanced Input duplicately fires input event when used in Widgets.

When creating a UserWidget and creating a process to receive input events with Enhanced Input, input events may be generated multiple times in duplicate. To reproduce this problem, create a Widget at runtime, add it to the screen with AddToPlayerScreen, and then destroy it with RemoveFromParent. After that, the same Widget is generated again and AddToPlayerScreen is performed, and the input events are generated in duplicate. 

After leaving the Widget for a minute or so, this event subsides and the input events are generated normally, but if the Widget is re-generated again, the event will reoccur.

1. Create UserWidget and make it handle input using Enhanced Input.

2. Play in editor.

3. Create widget with AddToViewport the widget (AddMappingContext)

    InputKey correctly the first time it is opened.

4. Delete widget with RemoveFromWidget (RemoveMappingContext)

5. Try step3 again
    Then, Input events are duplicated twice.
    Leave the widget open for around 1 minute.
    Duplicate input events stop occurring, but they recur when the widget is reopened