Roll Flutter Engine from 3a3a2807c3b6 to 683bca53d4d7 (3 revisions) (…

…#134778)

flutter/engine@3a3a280...683bca5

2023-09-14 bdero@google.com [Impeller] Assert IMPELLER_ENABLE_3D when importing scene_contents.h. (flutter/engine#45848)
2023-09-14 skia-flutter-autoroll@skia.org Roll Skia from 0f003d5748bc to 6bc9f5886ddf (2 revisions) (flutter/engine#45847)
2023-09-14 bdero@google.com [Impeller] Add AbsorbOpacity enum. (flutter/engine#45838)

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 bdero@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://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

bin/internal/engine.version

@@ -1 +1 @@
-3a3a2807c3b6e1a426536631b19d76b85f0f31b9
+683bca53d4d72e5bb891006dac0e75b667a792d8