Roll Skia from cbb0388767d2 to 4a8817a48b25 (4 revisions) (flutter#175202)

https://skia.googlesource.com/skia.git/+log/cbb0388767d2..4a8817a48b25

2025-09-10 [email protected] Roll
vulkan-deps from 90bb0f2095e9 to 482715c7d748 (6 revisions)
2025-09-10 [email protected] Fix difference between builder and path
2025-09-10 [email protected] Saturate in legacy shader when scaling
2025-09-10 [email protected] [graphite][vulkan] Adjust test
expectation for host image copy

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 [email protected],[email protected],[email protected] 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

Author: engine-flutter-autoroll

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': 'cbb0388767d2b8a5a5c1f5484a68fb0ff201561b',
+  'skia_revision': '4a8817a48b254e43761d31419263a67af7a7d32e',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.