Update AudioRecordingDisclosureBar animations

Currently the Mic icon slide from the right following the previous
notification pattern, as we changed it to a small one, we would want the
Microphone to Fade In and Fade Out.

Bug: 166459250
Test: make, flash
Test: atest CtsSystemUiTestCases:MicIndicatorTest
Change-Id: Ib628688110cf08b38929973153fbff5a3ca2d683