User Switcher: Dynamically set max col

We want to even out number of user tiles on each row.

Fixes: 218310680
Test: Manual
Change-Id: I5876867b0c6d9a6ab2a0dd363d8aa5881dfc5cb5
(cherry picked from commit c529723fa8e11f8293447c080b7c06cc6ee63017)
5 files changed