Add DisplayManager Logging

- Add logging to registering & unregistering listeners in display
  manager.
- Add logging to follow path of listener notifications

Bug: 284687313
Test: adb shell setprop persist.debug.vri_package <package-name>
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:1ab8ba34276a9602d5af1985e7ce9a7460a6ca7d)
Merged-In: I5093162cbfa632bafe6870c84177952becc82c50
Change-Id: I5093162cbfa632bafe6870c84177952becc82c50