Roll Flutter Engine from 9f2cf5c99b0f to 749e67a947bc (2 revisions) (#133618)

https://github.com/flutter/engine/compare/9f2cf5c99b0f...749e67a947bc

2023-08-29 bdero@google.com [Impeller] Document the capabilities. (flutter/engine#45253)
2023-08-29 xilaizhang@google.com [flutter roll] Revert "ios: remove shared_application and support app extension build" (flutter/engine#45250)

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 aaclarke@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

-9f2cf5c99b0fc0282db88846c1d97e6bc3560d28
+749e67a947bc0183c90ba40f39ef95584f65ef9b