Description of problem:

In the Helm Chart, the templates used to deploy the Orchestrator flavor make heavy use of Helm's lookup function to look up resources in a running cluster.
See https://github.com/search?q=repo%3Aredhat-developer%2Frhdh-chart%20lookup&type=code

As discussed in https://redhat-internal.slack.com/archives/C05HGAR2DT5/p1765379991189819?thread_ts=1765212646.522309&cid=C05HGAR2DT5 , ArgoCD doesn't execute `lookup` during template rendering (GitOps principles). It renders manifests using `helm template` behavior, and will not query the cluster when rendering the templates.
As a result, the lookup function would simply return an empty response, which might cause issues since the templates use information from the cluster to decide what to do next.

For now, let's document this as a known issue and add a note about issues with ArgoCD in the docs.

RHDHBUGS-2437 aims at investigating how we can avoid lookup completely.

More context in this Slack thread: https://redhat-internal.slack.com/archives/C05HGAR2DT5/p1765212646522309