[canvaskit] Fix some other usages of .ready

Leftover from https://skia-review.googlesource.com/c/skia/+/291182

Change-Id: I7350839d43299846e9e9cbc58425013eb063b041
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291356
Reviewed-by: Kevin Lubick <kjlubick@google.com>
6 files changed