Fix the condition to enable registerCleaner

It should only be enabled when both track_system_ui_context_before_wms
and clean_up_window_context_with_cleaner are enabled.

Test: atest WindowContextTest ContextTest
Flag: com.android.window.flags.clean_up_window_context_with_cleaner
Bug: 339727951
Change-Id: Ib60ef5197237854266b138d15bfeb87c7128a28c