Remove retrieveUserUsingJWT in version past 1.60

[JoshTheHero]

As of version 1.60 in FusionAuth, you can no longer use JWTs for User API Authentication. However in the SDK it still shows it as a potential method for things like retrieveUserUsingJWT. We should remove retrieveUserUsingJWT from the SDK or update the docs here to show it as no longer potential method.

[mooreds]

See also this tracking issue for all client libraries: FusionAuth/fusionauth-issues#3292