Allow HOST has no port (#22280) (#22409)

Fix #22274
Backport #22280 

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

modules/setting/setting.go

@@ -1334,7 +1334,7 @@ func NewServices() {
 	newCacheService()
 	newSessionService()
 	newCORSService()
-	newMailService()
+	parseMailerConfig(Cfg)
 	newRegisterMailService()
 	newNotifyMailService()
 	newProxyService()
@@ -1351,5 +1351,5 @@ func NewServices() {
 // NewServicesForInstall initializes the services for install
 func NewServicesForInstall() {
 	newService()
-	newMailService()
+	parseMailerConfig(Cfg)
 }