Alerting: Fix copying of recording rule fields

Recording rule fields were not being copied correctly when duplicating an alert rule. This manifests as missing `TargetDataSourceUID` fields from the `Record` part of the rule when rules in a group are re-ordered.

Added some additional tests to ensure we cover the generation of recording rules in tests and fixed the copying logic to ensure all fields are copied correctly.

(cherry picked from commit c73b3ccf6e)

pkg/services/ngalert/models/testing.go

@@ -561,6 +561,14 @@ func (a *AlertRuleMutators) WithAllRecordingRules() AlertRuleMutator {
 	}
 }
 
+func (a *AlertRuleMutators) WithoutTargetDataSource() AlertRuleMutator {
+	return func(rule *AlertRule) {
+		if rule.Record != nil {
+			rule.Record.TargetDatasourceUID = ""
+		}
+	}
+}
+
 func (a *AlertRuleMutators) WithMetric(metric string) AlertRuleMutator {
 	return func(rule *AlertRule) {
 		if rule.Record == nil {
@@ -1363,10 +1371,14 @@ func ConvertToRecordingRule(rule *AlertRule) {
 	if rule.Record.Metric == "" {
 		rule.Record.Metric = fmt.Sprintf("some_metric_%s", util.GenerateShortUID())
 	}
+	if rule.Record.TargetDatasourceUID == "" {
+		rule.Record.TargetDatasourceUID = util.GenerateShortUID()
+	}
 	rule.Condition = ""
 	rule.NoDataState = ""
 	rule.ExecErrState = ""
 	rule.For = 0
+	rule.KeepFiringFor = 0
 	rule.NotificationSettings = nil
 	rule.MissingSeriesEvalsToResolve = nil
 }