Use T50 base instead of T95

Colors with custom tones were using T95 as the base color, which has
very low chroma for most hues. By using T50, chroma is retained as
intended by design.

Bug: 213314628
Test: Manual inspection at runtime
Change-Id: I8ac519ea5e65abbb34b5ea2f64268474e0e2df66
10 files changed