Roll Flutter Engine from 0246484d2bae to 40a42796b129 (1 revision) (#144765)

https://github.com/flutter/engine/compare/0246484d2bae...40a42796b129

2024-03-07 kustermann@google.com Make @keepToString annotation work for web and non-web (flutter/engine#51251)

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 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://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

bin/internal/engine.version

-0246484d2bae0068900d2f9dd2d102fa9f30fc27
+40a42796b129f66a58370191458b6315fc6b90f8