Assert that newlines in coma separated arguments are ignored

This test is added to ensure that ksm can be invoked as follows and that
this is a "documented" feature.
```
<ksm> --metric-denylist="
    ^kube_.+_created$,
    ^kube_.+_metadata_resource_version$,
    ^kube_pod_completion_time$,
    ^kube_pod_status_scheduled$
  "
```
See: Usage in kube-prometheus jsonnet for example [1]

[1]: https://github.com/prometheus-operator/kube-prometheus/blob/9cf6111562f52107ae2b0b626db54f19b7e7d486/jsonnet/kube-prometheus/addons/ksm-lite.libsonnet#L18

Signed-off-by: Sunil Thaha <[email protected]>

Author: sthaha

pkg/options/types_test.go

@@ -106,6 +106,14 @@ func TestMetricSetSet(t *testing.T) {
 				"kube_daemonset_labels": {},
 			}),
 		},
+		{
+			Desc:  "newlines are ignored",
+			Value: "\n^kube_.+_annotations$,\n   ^kube_secret_labels$\n",
+			Wanted: MetricSet{
+				"^kube_secret_labels$":  struct{}{},
+				"^kube_.+_annotations$": struct{}{},
+			},
+		},
 	}
 
 	for _, test := range tests {