MM-8681 Adding config settings necessary for using CloudFront. (#8307)

* Adding config settings nessisary for using CloudFront.

* Adding new config settings to diagnostics.

app/diagnostics.go

@@ -243,6 +243,8 @@ func (a *App) trackConfig() {
 		"isdefault_image_proxy_type":                              isDefault(*cfg.ServiceSettings.ImageProxyType, ""),
 		"isdefault_image_proxy_url":                               isDefault(*cfg.ServiceSettings.ImageProxyURL, ""),
 		"isdefault_image_proxy_options":                           isDefault(*cfg.ServiceSettings.ImageProxyOptions, ""),
+		"websocket_url":                                           isDefault(*cfg.ServiceSettings.WebsocketURL, ""),
+		"allow_cookies_for_subdomains":                            *cfg.ServiceSettings.AllowCookiesForSubdomains,
 	})
 
 	a.SendDiagnostic(TRACK_CONFIG_TEAM, map[string]interface{}{