fix(billing): settle tiered retries with final group (#6518)

controller/relay.go

@@ -199,6 +199,10 @@ func Relay(c *gin.Context, relayFormat types.RelayFormat) {
 			newAPIError = channelErr
 			break
 		}
+		if billingErr := service.PrepareTieredBillingForSelectedGroup(c, relayInfo); billingErr != nil {
+			newAPIError = billingErr
+			break
+		}
 
 		addUsedChannel(c, channel.Id)
 		bodyStorage, bodyErr := common.GetBodyStorage(c)