Fix b/77867175: Clear all of NavigationPanel is missing

Two views shared the same states: mAnimating and mIsVisible thus some
alpha animations would be skipped due to ambiguous states.

This solution uses dedicated flags for each view and isolates
isVisible() from isSecondaryVisible(), making them more distinct.

Bug: 77867175
Test: runtest systemui
Change-Id: Id63b3498f9b5df581ca98202d227bd608c198d80