Merge "Clear preferred feature when unregistering MediaRouter2" into rvc-dev am: e7ae494759 am: 8cb3412ac2

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11846909

Change-Id: I2d03744a909ffd4b9e221ed4e822a2213e34139f