The error message for invalid pkce method is not affected by pkce_code_challenge_methods configuration

[ransombriggs]

Steps to reproduce

I am upgrading to get the functionality in #1735 because we do not accept the plain method but noticed that the error message still says that plain is an acceptable method.

What we need to do to see your problem or bug?

  Doorkeeper.configure
    pkce_code_challenge_methods ["S256"]
  end

        # from a request spec that we have for our hack that I am trying to remove
        get oauth_authorization_path,
            params: {
              client_id: application.uid,
              redirect_uri: application.redirect_uri,
              response_type: "code",
              scope: scope,
              code_challenge: code_challenge,
              code_challenge_method: "plain",
            },
            headers: {
              "cookie" => session_cookie,
            }

Expected behavior

The code challenge method must be S256.

Actual behavior

The code challenge method must be plain or S256.

[nbulaj]

I believe we can close this one via #1747 , right?

[ransombriggs]

yup, closing