Changes the return type of the client method RetreiveUserAction

[calwd]

I noticed that when I tried to import the package into my go project I was getting the following error:

# github.com/FusionAuth/go-client/pkg/fusionauth
../../../go/pkg/mod/github.com/!fusion!auth/go-client@v0.0.0-20230509031230-4b4943022898/pkg/fusionauth/Client.go:4437:81: undefined: UserinfoResponse
../../../go/pkg/mod/github.com/!fusion!auth/go-client@v0.0.0-20230509031230-4b4943022898/pkg/fusionauth/Client.go:4438:11: undefined: UserinfoResponse

So, I pulled down the source code for the project and noticed that the client method RetrieveUserInfoFromAccessToken was creating an error in compiling and testing.

Specifically, the method was trying to return a type called UserInfoResponse, but that struct does not exist in the client or domain files. So, I pulled the code history and noticed that the method previously returned a pointer to a UserResponse struct. I changed the return type to the UserResponse struct, tested the code out and it seemed to work.

Fixes #72

[robotdan]

This was a bug in the API def, UserinfoResponse is the correct type.

[robotdan]

For now I removed the API that uses that object in the client. I don't know if there is aw ay to map LinkedHashMap<String, Object> into Go - I think it would be map[string]interface{}, but I can't get the domain to compile.