Add necessary CI Steps to build the engine with the extension_safe flag (see: https://github.com/flutter/flutter/issues/124286), and upload the Flutter.framework and FlutterMacOS framework. The extension_safe frameworks needs to be code signed part of https://github.com/flutter/flutter/issues/124287
