Hide deprecated SkPaint::getBlendMode

Callers should use asBlendMode or getBlendMode_or

Bug: skia:12173
Change-Id: I8b62527a2ae11c9bf0c1473c4fffa53b38aa7017
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/425756
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Yegor Jbanov <yjbanov@google.com>
7 files changed