Identical liveness and readiness probes

[ZWang-AT]

The cloudnative-pg Helm chart uses identical health check commands for both
liveness and readiness probes, which violates Kubernetes best practices and fails
kube-score validation.

kube-score output:
[CRITICAL] Pod Probes Identical
· Container has the same readiness and liveness probe
Using the same probe for liveness and readiness is very likely
dangerous. It's generally better to avoid re-using the same probe.