MM-15494 Adding warning log when someone has configured a Mattermost push proxy with HTTP endpoint (#10869)

* MM-15494 Adding warning log when someone has configured a Mattermost push proxy with HTTP endpoint

* MM-15494 go fmt check

* MM-15494 Making function private

* MM-15494 Updating warning message

app/server.go

@@ -216,6 +216,8 @@ func NewServer(options ...Option) (*Server, error) {
 	mlog.Info(fmt.Sprintf("Current working directory is %v", pwd))
 	mlog.Info("Loaded config", mlog.String("source", s.configStore.String()))
 
+	s.checkPushNotificationServerUrl()
+
 	license := s.License()
 
 	if license == nil && len(s.Config().SqlSettings.DataSourceReplicas) > 1 {
@@ -620,6 +622,13 @@ func (a *App) OriginChecker() func(*http.Request) bool {
 	return nil
 }
 
+func (s *Server) checkPushNotificationServerUrl() {
+	notificationServer := *s.Config().EmailSettings.PushNotificationServer
+	if strings.HasPrefix(notificationServer, "http://") == true {
+		mlog.Warn("Your push notification server is configured with HTTP. For improved security, update to HTTPS in your configuration.")
+	}
+}
+
 func runSecurityJob(s *Server) {
 	doSecurity(s)
 	model.CreateRecurringTask("Security", func() {