Fix alarm preview volume

SeekBarVolumizer: do not use FLAG_BYPASS_INTERRUPTION_POLICY as
 there is no need to bypass DnD modes in seek bar for volume
 since they are disabled according to the DnD mode.
AudioService (PlaybackActivityMonitor): check both
 AudioAttributes flags BYPASS_INTERRUPTION_POLICY and
 BYPASS_MUTE for forced alarm playback (see b/63617557).

Test: see bug
Bug: 67578783
Change-Id: Iaf43f16d96d1ad8a1eacc73a050db767004ba96b