Ensure smoother transitions during fade in

When fading in, it is possible that a fade out operation is
already in progress. Applying a new volume shaper could
adversly impact  the transition (like sudden volume change)
or could also be ignored (if same operation type).

Prevent and ensure a smoother transition by replacing and
joining any existing fade out volume shaper.

Bug: 307354764
Test: atest -c FadeOutManager FadeConfigurations
Change-Id: If2412af84a2ab0e6090e9743591f8ef951c8952b