Add notification queue metrics (#16026)

internal/event/target/elasticsearch.go

@@ -167,6 +167,11 @@ func (target *ElasticsearchTarget) ID() event.TargetID {
 	return target.id
 }
 
+// Store returns any underlying store if set.
+func (target *ElasticsearchTarget) Store() event.TargetStore {
+	return target.store
+}
+
 // IsActive - Return true if target is up and active
 func (target *ElasticsearchTarget) IsActive() (bool, error) {
 	if err := target.init(); err != nil {