Currently, there doesn't seem to be a direct method in Intune to identify all services using the RDP protocol. However, if you wish to obtain this information on a Windows device using the command prompt, you can execute the following command from an elevated command prompt and go through all the services that use the 3389 protocol.
netstat -anob
To Filter with RDP protocol, you could use the below command:
netstat -anob | findstr :3389
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