I'm not really clear about your setup. At one point you seem to say that the laptop is serving as a wireless AP, and in another place it seems like there's a separate AP.
Run Telegram between the PC and the phone and run Wireshark on the PC. In normal use, your wireless AP is not going to repeat traffic destined for other devices to the PC you're using to run Wireshark.
If you must have two phones, you could associate them with two different access points and put a hub (not a switch) in the middle. Then connect the PC to the hub.
Edit: After I've read a little more about Telegram, it seems the clients do not talk to each other, they talk to Telegram's servers. So, you will need something like this:
If you run Wireshark on the laptop in promiscuous mode, you should be able to see the packets from the phone headed to the Telegram servers.
Note that the connection in the middle must be a hub, not a switch. You should be able to use two or more phones with this setup; I expect you'll see both talking to Telegram's server, and not to each other.