Dex v2.45+ incompatible with hardcoded runAsNonRoot

[clementnero]

Describe the bug

Dex v2.45.0+ fails to start when managed by argocd-operator due to runAsNonRoot verification failure. The operator hardcodes runAsNonRoot: true without setting runAsUser, but dex v2.45.0 (dexidp/dex#4517) changed from a numeric UID (USER 1001) to a named user (USER dex:dex). Kubernetes cannot verify runAsNonRoot for non-numeric users.

To Reproduce

1. Deploy ArgoCD using argocd-operator v0.16.0
2. Configure SSO with dex using version v2.45.0 or later:

   spec:
     sso:
       provider: dex
       dex:
         version: v2.45.0

3. Observe the dex pod fails with CrashLoopBackOff

Error message:

Error: container has runAsNonRoot and image has non-numeric user (dex), cannot verify user is non-root

Expected behavior
The dex container should start successfully.

One potential fix is to add a SecurityContext field to ArgoCDDexSpec (similar to #2050), allowing users to configure runAsUser via the ArgoCD CR.