Make customization CTA tile adapt to density and text size changes.

This changelist updates the customization CTA tile to better handle
size changes by:
- replacing set padding in favor of layout centering in buttons
- set remaining padding and sizing to stay constant to default sizing
- allow text size to grow within a set scaling factor (0-1.25)
- make middle text scrollable if necessary.

Fixes: 349515421
Fixes: 346672101
Test: manual - verified appearance is ok with text and display scaling
Flag: EXEMPT bugfix
Change-Id: I8379784d00fe69c5232a9330cc4edd8e5a664220