Roll Flutter Engine from 555ffa17b55c to b9b3269b0b2c (1 revision) (#137933)

https://github.com/flutter/engine/compare/555ffa17b55c...b9b3269b0b2c

2023-11-06 kustermann@google.com Fix FFI-based tonic layer to use proper C++ static_cast<>()s (flutter/engine#47644)

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

-555ffa17b55c38b7fa4c203c66ec673c3785d380
+b9b3269b0b2c67c7b45b8df9889e711dae8cce68