I'd argue that in this case the centralization helps because blocking GCM would kill all notifications for all apps. As long as they (Russia) are not willing to do that Telegram can use this as a side-channel to update their IPs for all clients.
The other option would be for google to turn push notifications off selectively for Telegram and only in russia. Not sure if they can/will do that.
If Google will comply with an order to remove apps from the store in certain regions then they can certainly comply with orders to filter push messages destined for specific apps as well.
The other option would be for google to turn push notifications off selectively for Telegram and only in russia. Not sure if they can/will do that.