Add fix to fix use of discovery.nypl.org in redirect_uri

[nonword]

What's this do? Fix all use of [qa-]discovery.nypl.org with [qa-]www.nypl.org in the redirect_uri for login.

Why are we doing this? (w/ JIRA link if applicable) We've found that the login flow started by the DFE hold-request route builds a login redirect_uri that uses the internal discovery.nypl.org hostname. It should not.

Do these changes have automated tests? None.

How should this be QAed? After deployment to QA:

• ensure logged out of QA RC
• navigate to a hold request page e.g. this
• note that the redirect returned ('Location' header) features a redirect_uri with qa-www.nypl.org instead of qa-discovery.nypl.org. After logging in, you should arrive at qa-www.nypl.org instead of qa-discovery.nypl.org

Dependencies for merging? Releasing to production? n/a

Has the application documentation been updated for these changes?

Did someone actually run this code to verify it works? Depends on host header, so easiest to test in QA.

[EdwinGuzman]

Approved but didn't check the base branch. The branch deployed to qa and production is TGR-50/remediation-update. Can you point this PR to that branch?

I haven't merged that branch into development yet but I will this week.