Update VolumeDialog to use a11y api for ui timeout value.

Using api introduced by A11yManager to get recommended ui
timeout value, and remove redundant logic of computing
a11y timeout in VolumeDialog.

Bug: 119284208
Test: atest VolumeDialogImplTest
Change-Id: I7611538e28be64ccceb5c75888a2f9105e624942
3 files changed