ActivityChooserView shows "see all" improperly.

1. The cooser was presenting the "Show all" option if the number
   of available activities was more than the initial max count of activities
   to be shown. Since the show all option is added to the drop down
   the latter becomes effectively one longer than the initial max activity
   count which may make the drop down taller than client expectats. Also
   this leads to the case where if the activities are one more than the
   initial activity count pressing the show all button will just replace
   the show all item with the activity that did not fit - this is somehow
   annoying to the user.

bug:5379282

Change-Id: I2693214cb0b66edb2a3bdffc01ed29139341111c