Roll Flutter Engine from 035740c1f90e to ec20731de6ff (2 revisions) (#137872)

https://github.com/flutter/engine/compare/035740c1f90e...ec20731de6ff

2023-11-03 skia-flutter-autoroll@skia.org Roll Dart SDK from 529fcd5bdffc to c52fb4fe2d86 (1 revision) (flutter/engine#47668)
2023-11-03 jacksongardner@google.com Bundle flutter.js via esbuild (flutter/engine#47573)

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

-035740c1f90e931d3f77bc4af6b4096dbf6d6234
+ec20731de6ff8b412a0e3edd541c977ca483a6ba