With the 4.x SDK, no way to determine values for a variation

[mehdi-pplx]

We have an odd little setup where we allow internal users to override flag's variation locally when testing things.
We accomplished this before with a function like:

def get_eppo_variation_configuration_by_name(flag_name: str, variation_name: str) -> Any:

which would get the flag configurations from the client, and manually grab the value from it. Something like this in the current SDK would be nice, as we are hackily doing it by reading through the JSON bytes exposed currently so that we can upgrade to 4.x.