Fix authorization state parameter

[Katsute]

The state parameter should not be a constant, it should be supplied as an optional parameter to verify that the request was not modified.

The state parameter is returned back in the same link as the code.

https://myanimelist.net/apiconfig/references/authorization#step-5-myanimelist-redirects-back-to-the-client

Some additional fields should also not be constant for the URL method.

https://myanimelist.net/apiconfig/references/authorization#step-2-client-requests-oauth-2.0-authentication