Unlike this projects, all other DA scrapers I found[0] require that both
"auth" and "auth_secure" are set.
While the current approach, for some reason, seems to have worked fine in
the past, it has stopped functioning on some systems, sometimes
permanently (apparently sometimes only temporarily).
I don't have the means to find out the reason behind that, since all
configurations I've tried (mobile, VPN, and regular connection +
4 seperate accounts) resulted in me being effectively logged out and
unable to view mature works after deleting the "auth_secure" cookie.
The "if auth_cookie" part might not actually be necessary, its only
purpose is to prevent unintended breakage due to lack of information
on my part.
[0]: b662b46a44 (diff-aab4e263d591d1c7f23d015a2e540a32R161)cbaecf5507 (diff-9f9821e7d744874a2fe42e0a69e4b14aR33)
e.g. If you were on an html work page on pixiv, clicked a link to a
different html work page on pixiv, and then clicked the bookmarklet,
then it used to fetch the source from the FIRST work you were on instead
of the second.
