[32/n] Delete LetterboxUiController and move dump()

Move dump() code into related AppCompat*Policy classes and
remove LetterboxUiController maintaining the same
tests temporarily.

Flag: EXEMPT refactor
Bug: 336807329
Test: atest WmTests:ActivityRefresherTests
Test: atest WmTests:AppCompatActivityRobot
Test: atest WmTests:CameraCompatFreeformPolicyTests
Test: atest WmTests:CameraStateMonitorTests
Test: atest WmTests:DisplayRotationCompatPolicyTests
Test: atest WmTests:LetterboxUiControllerTest

Change-Id: I54d10ebafd9bf1b932abeedabcdb35975dfa05d4