[skottie] Add text colorization GM

Expand existing SkottieColorizeGM to also handle text properties and
add text-focused instance.

Update layer names in one of the json assets to match expected demo
prefix ($).

TBR=
Change-Id: I076229067523fe597be66c611a8653897f995bc8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/342916
Reviewed-by: Florin Malita <fmalita@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
2 files changed