Roll Flutter Engine from c645eb6da8a9 to 6d7842d25f81 (1 revision) (#130992)

https://github.com/flutter/engine/compare/c645eb6da8a9...6d7842d25f81

2023-07-20 skia-flutter-autoroll@skia.org Roll Dart SDK from 603aacd8400f to 857c9a2ae14a (1 revision) (flutter/engine#43851)

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 bdero@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

bin/internal/engine.version

-c645eb6da8a9e3ca22d25a240b608fc643039a51
+6d7842d25f81004bbd3125ecbec167db69fa241f