Use updated gni source list (flutter#56627)

In https://skia-review.googlesource.com/c/skia/+/884096, Skia broke up
this gni file list into Ganesh and Graphite specific code. Since Flutter
only needs Ganesh sources, this can be made more precise.

## Pre-launch Checklist

- [ x ] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [ x ] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [ x ] I read and followed the [Flutter Style Guide] and the [C++,
Objective-C, Java style guides].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ x ] I added new tests to check the change I am making or feature I
am adding, or the PR is [test-exempt]. See [testing the engine] for
instructions on writing and running engine tests.
- [ x ] I updated/added relevant documentation (doc comments with
`///`).
- [ x ] I signed the [CLA].
- [ x ] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[C++, Objective-C, Java style guides]:
https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
[testing the engine]:
https://github.com/flutter/flutter/wiki/Testing-the-engine
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/wiki/Chat

skia/BUILD.gn

@@ -649,7 +649,7 @@ skia_component("skia") {
   sources += skia_codec_decode_bmp
   sources += skia_encode_srcs
   sources += skia_sksl_core_sources
-  sources += skia_sksl_default_module_sources
+  sources += skia_sksl_core_module_sources
   sources += skia_ports_sources
   sources += [
     "$_skia_root/src/android/SkAndroidFrameworkUtils.cpp",