Hi,
At the moment, it is not possible to restrict the hotspot feature using Cisco Meraki EMM solution.
However, it can be turned off for clients individually.
In Dashboard, you would need to go to System Manager > Monitor > Clients, then select a client, and in the MDM commands you will find "Data Settings", which will give you the option to Enable/Disable Personal Hotspot.
A few things to take into consideration:
-The device needs to be supervised.
-Clients have the option to turn it back on manually in the device itself.