MM-8604: emit config/license websocket events (#8371)

model/websocket_message.go

@@ -44,6 +44,8 @@ const (
 	WEBSOCKET_EVENT_CHANNEL_VIEWED      = "channel_viewed"
 	WEBSOCKET_EVENT_PLUGIN_ACTIVATED    = "plugin_activated"   // EXPERIMENTAL - SUBJECT TO CHANGE
 	WEBSOCKET_EVENT_PLUGIN_DEACTIVATED  = "plugin_deactivated" // EXPERIMENTAL - SUBJECT TO CHANGE
+	WEBSOCKET_EVENT_LICENSE_CHANGED     = "license_changed"
+	WEBSOCKET_EVENT_CONFIG_CHANGED      = "config_changed"
 )
 
 type WebSocketMessage interface {