EditText - can not drag handles in extracted mode

In TextView's onPreDraw method, startSelectionActionMode()
is called, but the selection has already been started so
in startSelectionActionMode() it shows the
insertionController which hides the selectionController.
Fix this by adding a check to start the action mode only
if it is not already started.

Bug: 22028858
Change-Id: I2999423155b7a63a7d879bc8ea5032e17dff459f