Blender Git Loki

Fix T67446: UV Editor: support island select mode for box/circle/lasso
selections

Previously this was only supported in single click selections, doing an
island selection with box/circle/lasso would just select individual
vertices instead. Now selects islands properly.

This also unifys some logic between box/circle/lasso:
- use early selection test from lasso [makes things faster] in box/
circle
- circle wasnt checking visible face