Decrease avatar and sender name sizes in MessagingStyle

This reverts commit a738ca4170a8fe6f871c75bcb17960bdaeac8c56.

Addressed this with new messaging layout

Bug: 150905003
Test: add messaging notification, observe normal sizes
Change-Id: I69b33b0c30a3237b16a23632b9151015572298f8
4 files changed