Acknowledge mouse button events as position tellers (to make picking more solid; for instance, the touch mouse is raised with a mouse unpressed event that may have a more current position)
Forget mouse position for physics if touch mouse raised (because the position known as last is no longer meaningful)
Remove needless check for mouse over/exit (now there's code to inject an spurious move for cases where camera/objects have moved)
Restrict 2D mouse over/exit to mouse events (including emulated from touch; true touches shouldn't trigger the signals)
Fixes#26460.