Fix that authorization code is returned by fragment if response_mode is fragament

[nhosoya]

Summary

There is a problem that the authorization code is returned in the query even if "fragment" is specified for response_mode in the authorization request.

Other Information

Whether the authorization code is returned as a query or as a fragment is determined by the following in CodeResponse.

doorkeeper/lib/doorkeeper/oauth/code_response.rb

Lines 43 to 47 in a56b1a5

	elsif response_on_fragment
	Authorization::URIBuilder.uri_with_fragment(pre_auth.redirect_uri, body)
	else
	Authorization::URIBuilder.uri_with_query(pre_auth.redirect_uri, body)
	end

In order for this to be determined correctly, response_on_fragment must be passed when initializing CodeResponse.
However, since response_on_fragment is not specified when CodeReponse is initialized in CodeRequest.
Therefore, the authorization code is always returned in query.

[nbulaj]

LGTM 👍