API Catalog not working with SSO when accessed from Desktop

[1000TurquoisePogs]

In the latest nightly builds that zowe-install-packaging is producing, opening the API catalog within the Desktop after a valid login from the Gateway produces a login screen on the catalog. That is, the catalog is not working with SSO when accessed from the Desktop.

The behavior is only in the nightly builds, it is not in any release such as v3.1, so it must be some recent change.

Zowe's integration testing in zowe-install-packaging hasn't been working for a few weeks due to a failing test which checks if the API catalog works in the Desktop. As a result, no approved install improvements have been merged since.

How to reproduce:

1. Take a 3.2 staging build
2. go to desktop within gateway, login
3. open api catalog - notice it presents a login screen (sso not working?)

then, clear everything or go to a private session or whatever.

1. Go to gateway homepage
2. Click catalog link, login
3. Go to desktop in same window
4. you should see no extra login, sso is working
5. open catalog in desktop, you should see no login, sso is still working

in both cases, you should see that the request and cookie sent to the same catalog URL results in different behavior from the catalog.
so, its not clear to me why there is different behavior, but in v3.1 and below, accessing the API catalog by any means would honor SSO.

The recent change #4007 is unrelated.
I have tested without the change and have the same issue regardless.