Move IME log to WindowTokenClient

IMF has the requirement to debug if the configuration is dispatched
to InputMethodService. Since we migrated InputMethodService to
WindowProviderService, we should also move the debug logic to
WindowContext module because config updates will be no longer from
ActivityThread.

Test: build & run
Bug: 135719017
Change-Id: I248c90f36249a6a4537228f7b0204f0d4466ebc7