CommonUI uses cached geometry that might be zero sized for gamepad focus

Reproduced 3/3 times, issue also occurs in //UE5/Release-5.0 - CL 20979098 Binary. Confirmed NOT a Regression.

Workaround for issue is to have a text box in the vertical box before any buttons; first button will always be in focus then. If user moves control stick, buttons will start focusing.

1. Enable Common UI
2. Make the default input type be "Gamepad" under common input settings
3. Create a root UI widget with a common UI stack
4. Create a UI widget that extends common activateable widget
5. Add a vertical box with 2 buttons that extend from common button base
6. Tell the root UI widget to push an instance of the second widget onto its stack
7. Put the root view into the main viewport on begin play
8. Set game input mode to UI only on player controller in begin play and show cursor
9. In the widget that has the button, override its getDesiredFocusTarget to return the first button
10. PIE

Actual Result: First button will not be in focus. If player presses the controller's "confirm" button (A for Xbox, X for PS, etc), controller input will no longer be read unless a different input device is used (like mouse cursor)

Expected Result: The first button is in focus on Begin Play.