Fix "Select All" in extracted mode

Stop calling onExtractTextContextMenuItem if "Select All"
is selected (the action does not modify text thus does
not need batch editing). Editor#finishBatchEdit reports
that text changed which in turn can stop the action mode
and the selection after it was started by onPreDraw.

Bug: 22059417
Change-Id: I5354cbe4bae374e0d5f3de39616336170ee33b92