[FR] Provide a flag to add exclude empty collections annotations in codegen

[nampham148]

What happened?

We are having a use case where we send requests across different stacks, which means there are no version constraint between clients and servers. As it is, if a new collection field is added and client takes the update before server, the server will throw on unknown field even if the client hasn't used this new field yet (sending an empty collection). It'd be nice to exclude the empty collection field in the request in this case, so that we have a bit more forward compatibility.

What did you want to happen?

We want a flag to allow excluding empty collections from objects. It would be the collection counter part of this excludeEmptyOptionals flag.