Add Monitoring coreos.com custom resources to the scheme

When Prometheus Redpanda helm chart dependency is enabled, then DecodeYAMLFrom
is not working due to missing ServiceMonitor custom resource in scheme.
```
=== CONT  TestConfigMap/14-prometheus-no-tls-values.yaml
    chart_test.go:182:
        	Error Trace:	/Users/rafalkorepta/workspace/redpanda/helm-charts/charts/redpanda/chart_test.go:182
        	Error:      	Received unexpected error:
        	            	no kind "ServiceMonitor" is registered for version "monitoring.coreos.com/v1" in scheme "pkg/runtime/scheme.go:100"
        	Test:       	TestConfigMap/14-prometheus-no-tls-values.yaml
    --- FAIL: TestConfigMap/14-prometheus-no-tls-values.yaml (0.08s)
```

charts/redpanda/chart.go

@@ -5,6 +5,7 @@ import (
 	_ "embed"
 
 	certmanagerv1 "github.com/cert-manager/cert-manager/pkg/apis/certmanager/v1"
+	monitoringv1 "github.com/prometheus-operator/prometheus-operator/pkg/apis/monitoring/v1"
 	"github.com/redpanda-data/helm-charts/pkg/gotohelm/helmette"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/kubernetes/scheme"
@@ -25,6 +26,7 @@ var (
 func init() {
 	must(scheme.AddToScheme(Scheme))
 	must(certmanagerv1.AddToScheme(Scheme))
+	must(monitoringv1.AddToScheme(Scheme))
 
 	// NB: We can't directly unmarshal into a helmette.Chart as adding json
 	// tags to it breaks gotohelm.