Use canvas.setMode() on rotate/resize grip mousedown

Without this, you can create a text element, thereby entering into "textedit" mode, and by immediately resizing or rotating it, be taken out of "textedit" mode without the text cursor being cleared (it will still be blinking and in the wrong place). Calling `canvas.setMode()` insures that `textActions.clear()` is called which takes care of the cursor.