Remove all Dependency.get(ActivityStarterDelegate.class) calls.

It was only called in StatusBar so that StatusBar could pass itself in.
Instead, inject StatusBar directly (as an Optional).

If we ever want a different implementation, we can handle that in the
future, but right now, StatusBar was the only one ever set.

Bug: 141882822
Test: atest SystemUITests
Change-Id: Ia23b8f678ea2ac0eb4e8114f700bf703f48740e7