Move KeyboardBacklightListener to InputManagerGlobal

Move KeyboardBacklightListener, along with its associated
functions from InputManager to InputManagerGlobal.
Associated CLs for this refactoring:
- ag/21609952
- ag/21699437
- ag/21849880
- ag/21853350

Bug: b/267758905
Test: Pre-submit
Change-Id: I8f189a3c4aa1746ce9c225a19925a78375ec88b2