Fix issue where the notification could snap to the menu while its invisible

1) If the snap back animation is cancelled, the menu shouldn't be reset
   because it hasn't actually been snapped back -- this could happen when
   the menu was being shown and then the icon alpha would get set to 0
   resulting in notification snapped to menu but no menu visible
2) Cancel the callback to fade the menu in on dismiss to match original
   behavior before refactor of NMR

Test: manual - no clear repro steps for this, I could get it by
      violently moving a notification back and forth, with this patch
      I haven't been able to repro it.
Bug: 37320279
Change-Id: I4eea37e3c454e7324d0e295b0ec2fe022d219253