You have to upgrade your MC to version 15.3x+.

The v15.3 comes with the option to deactivate the "pull to refresh" setting for SOTI Surf and many more
settings.

Upgrading a server often involves many other considerations, especially when a server is managing a large number of devices of different device platforms and modes.   If the MobiControl device agent deployed/upgraded on your devices of interest is current enough to support the script command

     sendinfo net.soti.action.surf DISABLEPULLTOREFRESH     0 | 1

then you can just send this script with the right argument to the device agent without upgrading your MobiControl server to v15.3 or higher.