[AI] GameplayDebugger can be enabled by key press when a Slate widget is focused.

Found by licensee. After debugging, it appears that the Slate input is consuming the KeyDown event which adds the apostrophe, but it passes the KeyUp event back to Player input. The gameplay debugger catches the KeyUp event which then calls to toggle the gameplay debugger.

Expected result would be that input would either be fully consumed by Slate input or that the GameplayDebugger would check for some value set in the KeyDown event which runs a separate function before toggling the GameplayDebugger.

1. Create a Widget Blueprint containing an EditableTextBox
2. Add widget to Viewport while PIE'ing
3. Click in text box
4. Press '
5. Textbox contains ' as well as GameplayDebugger being pulled up