Refine default vibration behavior for vibrate-only

Keep the classic vibration effect as default for
haptic-only mode. Support the custom vibration playback
only if the user choose a new vibration via settings.

Also if the user choose a new vibration, avoid haptic channel
mute when ramping ringer enabled.

Flag: android.media.audio.enable_ringtone_haptics_customization
Bug: 394231980
Test: atest RingerTest
Change-Id: I3dab1edc3a5d7a64a65d6350a99ad9517d999f2b