Use last volume level instead of the level specified in Intent

Intents were processed asynchronously and the order is not garenteed.
When devices send Volume change intent continuously in a short time
window the volume bar will move back and forth on the UI. This issue
can be reproduce on subatomic devices easily by adjusting the volume
continuously after switch between apps.

Flag: EXEMPT bugfix
Bug: 361354592
Test: Test on a TV subatomic device (loki)
Change-Id: Ib8c0b06e3dbd48cb18230ff1b7b021e9243e2007