Attempting to override the http scheme for each request is not working
for every request type. Let's set the client config scheme to HTTPS by default.
Move away from `NewClientWithAccessKey` and instead create an access key
separately and then use `NewClientWithOptions` to create the client with a
custom config using "HTTPS" for the scheme.
Also remove the scheme override for each request.

This reverts commit 0b659af.

That was meant to be a temporary measure but lingered for a while. As
mentioned there, ideally, we'd build both, but if we only build one, let
it be RHCOS.

It doesn't work properly against these rhcos- branches anyway. Let's
just limit the testing to building the container and running check
and unittest tests.

(cherry picked from commit 511a61d)