Roll Flutter Engine from 4d67f267b115 to 6f6649bdfef2 (1 revision) (#141920)

https://github.com/flutter/engine/compare/4d67f267b115...6f6649bdfef2

2024-01-20 skia-flutter-autoroll@skia.org Roll Skia from 61a2dcff4194 to 3cac1efbdd7a (4 revisions) (flutter/engine#49916)

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 jonahwilliams@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://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

-4d67f267b1158e8d361615aa7054166b6ffc2136
+6f6649bdfef2a4bdcbc3924bb78b284d6af26062