Dialer: Update landscape layout to match 4.4.3 codebase

Change-Id: Ib7768010ba88581030bdda902751ca7593f18b46
Hide shadow overlay for contact tiles with letter tile avatars

Also tweak layout of letter tiles to better match redlines

Bug: 13101785
Change-Id: I1846947a389bbdccc30bfe388b24e80e8724a357
(cherry picked from commit 7846f2e0ed4def3202029f6ef5d6e0b350de0986)