Fix Interaction not resetting to None sometimes

[Davier]

This corrects two bugs in ui_focus_system:

• When clicking and releasing a button in a single frame, it stays stuck in Interaction::Clicked until the next mouse click
• It's possible for nodes to not be un-hovered in some cases with FocusPolicy::Pass, such as when they get covered by new nodes

I noticed that touch input is using just_released instead of just_pressed for clicking, which means that the 1st issue may have been a feature for them. With this PR, the buttons would no longer stay stuck in the Clicked state after any released touch. If that behaviour was intended I can easily re-introduce it.

[cart]

This looks good to me. Touch input appears to be completely broken ... not due to this pr, but due to the recent move to using window.cursor_position (which touch does not set).

I think we'll want to incorporate the touch location too (in a separate pr).