Add device dimension data to wallpaper backup flow

This CL adds device dimension data for the src device that the backup was performed on (in the backup flow). It also adds logging to indicate when the backup
occuring from a small to a large device.

unit test results: http://ab/I34300010251184653

Flag: NONE
Bug: 324257610
Test: atest WallpaperBackupAgentTest --request-upload-result
Change-Id: Ifa14a8fc2e7f2955157cb41eb128ebe27deabfc2