[skottie] Improved animation params parsing

Some BM versions wrap the Bezier animation params into arrays.

TBR=
Change-Id: I376b1ed2079105066413b513c3df33a61440cf41
Reviewed-on: https://skia-review.googlesource.com/98580
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
2 files changed