Support dispatch audio focus with fade manager config

Dispatch of audio focus change from external focus policies
do not consider fade. This results in audio crossover
when transitioning between multiple apps of similar
usage types.

This commit adds new API to be used by external focus
policies to dispatch audio focus change with fade. The
API also supports transient fade manager configuration
that is prioritized over the default or the configuration
set through AudioPolicy.

Bug: 186905459
Bug: 314521818
API-Coverage-Bug: 308666800
Test: atest -c FadeManagerConfigurationUnitTest

Change-Id: Ifda86d4ca618d6926f85b0c9e29f70c436c9618c