Reschedule timeout when accessibility event occurs

Fix setting up the accessibility delegate of dialog view. We need to set
the accessibility delegate of volume dialog whenever we assign a new
value to volume dialog. So we need to call Accessibilty.init everytime
we initialize the dialog.

Fixes: 201730401
Test: atest VolumeDialogImplTest
Test: Checked the timeout is rescheduled when there is an a11y event.

Change-Id: Ia8c807b5831559505813f4b81610c8e05a1bb41f