[StyleBuilder] Templatize ColorPropertyFunctions for style builder.

This patch templatizes:
ColorPropertyFunctions::GetUnvisitedColor
ColorPropertyFunctions::GetVisitedColor

As we need to use a ComputedStyleBuilder within:
CSSColorInterpolationType::ResolveInterpolableColor

and a ComputedStyle within:
CSSColorInterpolationType::MaybeConvert*

There should be no behaviour change.

Bug: 1377295
Change-Id: I0ec9bf0314409ce577dbb660a0ee278b05d91870
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4035649
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1073366}