[sksg] Initial text support

Use the new node type for SkottieSlide2 labels.

TBR=

Change-Id: Icd6a4faf1c281bd83a2331c0072d1a6ed71acc09
Reviewed-on: https://skia-review.googlesource.com/102441
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
10 files changed