Fix TimePickerDialog positive button clicks.

With my TimePickerDialog change to support keyboard based input I
accidentally broke TimePickerDialog#onClick as it was no longer being
called, instead it was calling TimeSetListener directly. This CL changes
the logic back to use onClick again.

Bug: 36042834
Test: Locally tested FitBit app.
Change-Id: I47d5563c99cc46eaaf2b1d4a96483d6825fc5805