Center apps Preference title when there is no summary

Hide apps Preference summary when a summary is empty
then its title will be vertically centered.

Bug: 229646669
Test: manual visual
      Settings -> Apps -> See all apps
      Settings -> Notifications -> App settings
      Settings -> Storage -> Apps
      Settings -> System -> Language & input -> App Languages
Change-Id: I6fceba243e2ccac9ea180b940b571da07e1ba805
Merged-In: I6fceba243e2ccac9ea180b940b571da07e1ba805