Alerting: use hash of labels instead of labels string as the alert state cache key (#88956)

* Alerting: use hash instead of labels as the cache key
* Use data.Labels.Fingerprint to calculate the cache key

pkg/services/ngalert/models/instance_labels_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/grafana/grafana-plugin-sdk-go/data"
 	"github.com/stretchr/testify/require"
 )
 
@@ -39,6 +40,19 @@ func TestTupleLabelsToLabels(t *testing.T) {
 	})
 }
 
+func TestInstanceLabelsFingerprint(t *testing.T) {
+	t.Run("returns labels fingerprint", func(t *testing.T) {
+		labels := InstanceLabels{
+			"foo": "bar",
+			"baz": "qux",
+		}
+
+		fingerprint := labels.Fingerprint()
+		expectedFingerprint := data.Labels(labels).Fingerprint()
+		require.Equal(t, expectedFingerprint, fingerprint)
+	})
+}
+
 func BenchmarkTupleLabelsToLabels(b *testing.B) {
 	b.Run("10 labels", func(b *testing.B) {
 		in := make(tupleLabels, 0, 10)