[skottie] Stage locale change

Two issues:

1) Clients depend on struct layout for initialization -> move the new
field to the end of the structure.
2) SkUnicode is not always available (e.g. CoreText config on iOS) ->
use explicit bidi level constants instead (SkShaper takes uint8_t's).

Bug: b/263268721
Change-Id: I8e95b5512761a8487b5aa1556455ee502bbe8344
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/762080
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
4 files changed