Allow HOST has no port (#22280)

Fix #22274

This PR will allow `HOST` without port. Then a default port will be
given in future steps.

modules/setting/setting.go

@@ -1340,7 +1340,7 @@ func NewServices() {
 	newCacheService()
 	newSessionService()
 	newCORSService()
-	newMailService()
+	parseMailerConfig(Cfg)
 	newRegisterMailService()
 	newNotifyMailService()
 	newProxyService()
@@ -1357,5 +1357,5 @@ func NewServices() {
 // NewServicesForInstall initializes the services for install
 func NewServicesForInstall() {
 	newService()
-	newMailService()
+	parseMailerConfig(Cfg)
 }