Roll Skia from fed87fbbe49e to 8b706494a21b (1 revision) (flutter#54353)

https://skia.googlesource.com/skia.git/+log/fed87fbbe49e..8b706494a21b

2024-08-05 jmbetancourt@google.com [skottie] add child shader support for custom SkSL effects

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC brianosman@google.com,jacksongardner@google.com,rmistry@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Skia: https://bugs.chromium.org/p/skia/issues/entry
To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

DEPS

@@ -14,7 +14,7 @@ vars = {
   'flutter_git': 'https://flutter.googlesource.com',
   'skia_git': 'https://skia.googlesource.com',
   'llvm_git': 'https://llvm.googlesource.com',
-  'skia_revision': 'fed87fbbe49e4ff1b890a12a8b2991deb6b19d5d',
+  'skia_revision': '8b706494a21bc48b410c14cfc55a833ce276e872',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.

ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: e9c88cf74a53750faabffc3cffed378a
+Signature: ce55cff03174f60aeba1da6914eb03a8
 
 ====================================================================================================
 LIBRARY: etc1