Those images that are pulled from Dockerhub will cause pull failures
on some test clusters due to Dockerhub rate limiting.
Because we already have some images that we use for testing, and
because those images are already pre-loaded onto our CI clusters
to make the tests faster, use one of those images and always specify
PullIfNotPresent to avoid pulling the image again during the integration
test.
TestSimultaneousLDAPRequestsOnSingleProvider proved to be unreliable
on AKS due to some kind of kubectl port-forward issue, so only
run the LDAP client's integration tests on Kind. They are testing
the integration between the client code and the OpenLDAP test server,
not testing anything about Kubernetes, so running only on Kind should
give us sufficient test coverage.
