Use setPressed() for better touch-down behavior

After I59f472a9d864f4abcc4f692fef0a13f004348432, we are able to rely
on setPressed(true) for "touch-down" behavior.

- Rely on setPressed()
- stop overriding shouldDelayChildPressedState() for having system-wide
  delay behavior.
- start sound on setPressed(true)

Bug: 5965380
Bug: 6007908
Bug: 5749440
Change-Id: I5dd440eee1d70992d0db7835c215053904ac3e20