Roll Flutter Engine from 3b0469b0c718 to 503b84295462 (1 revision) (#136928)

https://github.com/flutter/engine/compare/3b0469b0c718...503b84295462

2023-10-19 dkwingsmt@users.noreply.github.com Reland 2 (part 2): Enforce the rule of calling `FlutterView.Render` (flutter/engine#47095)

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 jimgraham@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

-3b0469b0c718cdd69570c0830743460d5f159200
+503b84295462ab2a9ebeb9b4d78d8a6d0aafa03e