Partial revert of "Prepare LightBarController for multi display"

This partially reverts commit 88228a8a.

Reason for revert: b/379344858

Fully reverts the changes in NavigationBar.java, and creates a
"LegacyFactory" that instantiates the dependencies in the same way as
they were being instantiated before.

Fixes: 379344858
Test: atest SystemUITests
Flag: EXEMPT bug fix
Change-Id: Iccb1df6725d6529a8eeff5b0f081b150747e5077