fix [#35194] Change view while LoopCut is active breaks the cut options

use edge-index rather then mouse coords for loopcut so the viewport doesn't interfere.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56479 954f8c5b-7b00-dc11-b283-0030488c597c