Make Glanceable Hub dimensions consistent between density changes.

This changelist scales values for Glanceable Hub dimensions to adjust
for changes in density. This ensures the overall sizing of the grid
stays the same regardless of the set density. Content within the grid
is free to scale within their bounds.

Test: manual - ensured changing density does not affect the grid sizing
Flag: EXEMPT bugfix
Fixes: 347168353
Change-Id: I657a2543f6e75add4a77960fb3c117dc39c2865b