Make sure we set correct GrPixelConfig in promise images

Land just the Promise image fixes from, https://skia-review.googlesource.com/c/skia/+/114261

Bug: skia:
Change-Id: I917cf2c1f5c6e51f9d7f1d3ec4526db551e89d84
Reviewed-on: https://skia-review.googlesource.com/114472
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
2 files changed