Make LightBarTransitionsController injectable.

Give it a factory that allows it be injected, removing its reliance on
Dependency#get.

More changes to follow this one, as NavigationBarTransitions is still
not injectable, so more calls to Dependency#get had to be added to
compensate.

Bug: 218354102
Test: atest SystemUITests
Change-Id: I891467cf0e49f78577533eb8c74fe26816f8d854