Refactor: move response_type check in pre_authorization to a method to be easily to override

[linhdangduy]

Summary

This pull request refactors error_response method of pre_authorization in authorization request.

In Oauth2, response_on_fragment=true when response_type=token (which is implicit flow).
But OIDC introduces other response_type which also define that response_on_fragment=true (response_type = id_token or id_token token...)

I move the response_type check to response_on_fragment? method, so it could be easily override this behavior like:

def response_on_fragment?
  super || response_type == "id_token"
end

References:

https://openid.net/specs/openid-connect-core-1_0.html#ImplicitAuthRequest

[doorkeeper-bot]

	1 Warning
⚠️	There’re library changes, but not tests. That’s OK as long as you’re refactoring existing code.

Generated by 🚫 Danger

[linhdangduy]

Haven't found out where to fix to avoid the coverage decreased error. 👀
I think this pull is just a refactoring work.

[nbulaj]

LGTM

[nbulaj]

Agree @linhdangduy