[usage] Don't pass '0001-01-01T00:15:00Z' timestamps through the CostCenter API when it should be undefined 🙃

Author: jankeromnes

components/usage/pkg/apiv1/usage.go

@@ -190,12 +190,20 @@ func (s *UsageService) GetCostCenter(ctx context.Context, in *v1.GetCostCenterRe
 }
 
 func dbCostCenterToAPI(c db.CostCenter) *v1.CostCenter {
+	NextBillingTime := timestamppb.New(c.NextBillingTime.Time())
+	if !c.NextBillingTime.IsSet() {
+		NextBillingTime = nil
+	}
+	BillingCycleStart := timestamppb.New(c.BillingCycleStart.Time())
+	if !c.BillingCycleStart.IsSet() {
+		BillingCycleStart = nil
+	}
 	return &v1.CostCenter{
 		AttributionId:     string(c.ID),
 		SpendingLimit:     c.SpendingLimit,
 		BillingStrategy:   convertBillingStrategyToAPI(c.BillingStrategy),
-		NextBillingTime:   timestamppb.New(c.NextBillingTime.Time()),
-		BillingCycleStart: timestamppb.New(c.BillingCycleStart.Time()),
+		NextBillingTime:   NextBillingTime,
+		BillingCycleStart: BillingCycleStart,
 	}
 }