[Impeller] Add validation forbidding SamplerAddressMode::kDecal on the OpenGLES backend (#43094)

Fixes uncontrolled crash when kDecal is used (as seen on
https://github.com/flutter/engine/pull/43087).
https://dart.googlesource.com/external/github.com/flutter/engine/+/e58ebef5fccbc49d451dc3c484e9347245a2d5f7
1 file changed
tree: bc7ea3f4c0228ac400a419d0c1f255b5785b1dfe
  1. commits.json