Update platform_k8s_hpa_metrics.j2

[SuperThinking]

Make the numerator exact match (same as the denominator)

We could've also used a query like:

Grafana

kube_deployment_status_replicas_available{deployment=~"^{{deployment_name}}*"} / on (deployment) label_replace(kube_horizontalpodautoscaler_spec_min_replicas{horizontalpodautoscaler=~"^{{hpa_name}}.*"}, "deployment", "$1", "horizontalpodautoscaler", "(.*)")

but this assumes that hpa_name == deployment_name which might not always be true