Disallow snapping to 80/90% and EBU R95 safe areas if not on the visible grid lines

[TRA]

Currently, the VUI for Size, Position and Rotate, Simple Text, Crop: Rectangle, etc. as well as the VUI for Corner Pin snap to invisible lines extending from safe area rectangles.

I think I made it possible to disable snapping while the handles are not on the safe area rectangle lines:

Disable snapping if not on safe area rectangle lines