Fix `curl` tests in nexus pipelines

General MR

Summary

This MR updates the curl invocation in Nexus' scripts to use the -L flag, allowing calls to upgrade from HTTP to HTTPS and allowing the in-cluster http calls handled at the package level to work the same way the https calls in BB umbrella need to work.

EDIT: Additionally, I had to update the script to have special handling for VirtualService testing (as is handled in BB umbrella) vs Service testing (as is done in this package's pipeline).

Relevant logs/screenshots

A test evidence MR in BB umbrella shows what configuration changes are needed on that side for a passing pipeline: big-bang/bigbang!6141 (closed)

Linked Issue

#165 (closed)

Upgrade Notices

N/A