Roll Flutter Engine from 39be0fc34503 to ec3e988099be (2 revisions) (#137637)

https://github.com/flutter/engine/compare/39be0fc34503...ec3e988099be

2023-10-31 jason-simmons@users.noreply.github.com [Impeller] Do not return a null Contents if a Paint's blur filter yields an empty coverage rect (flutter/engine#47496)
2023-10-31 skia-flutter-autoroll@skia.org Roll Dart SDK from 776fad25647a to eecb650a0fb9 (1 revision) (flutter/engine#47514)

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

-39be0fc34503a527134f6c46232a25c117b3edd7
+ec3e988099be15019a38abd4b6e9d1e456ff7edc