Add adaptive haptics scaling to external vibrations

We've added a new parcelable object, ExternalVibrationScale, which will
hold both vibration scale level and adaptive haptics scale. This will be
returned by onExternalVibrationStart and used when scaling external
vibrations.

Bug: 305957324
Test: atest VibrationScalerTest
Change-Id: If745ca266e1e7f97a9933f7babfb99ba4246380d