OpenAI - Ordering changes for internal constructors

[JoshLove-msft]

The ordering of parameters has changed for various internal constructors as compared with Autorest. This also influences the order of serialization. None of this should be considered part of the public contract, but if there isn't a good reason for us to change the order, we should retain the autorest ordering to make it easier for customers to migrate.

[JoshLove-msft]

Discussed and this should be considered a non-goal. The ordering of serialization won't even cause test failures anymore when using the Test Proxy as the proxy matching has been fixed to not rely on ordering.