Manual roll requested by zra@google.com

https://github.com/flutter/engine/compare/8ca16cba8c38...78f41a8f2f06

2023-05-09 skia-flutter-autoroll@skia.org Roll Dart SDK from
4b4c0325fd5b to 2cf089614e1c (3 revisions) (flutter/engine#41866)
2023-05-09 lhkbob@gmail.com Remove staging flag (flutter/engine#41843)

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

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://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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