[skottie] Scale the editor cursor to account for auto-sizing

When using one of the auto-sizing modes, the final font size differs
from the original/specified font size.

Plumb the auto-sizing scale through the glyph decorator API, and adjust
the cursor size to match the actual font size.

Bug: b/259298707
Change-Id: I2bdbda8021086acee5d6e8c2f78f3170196a87f8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/648176
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
4 files changed