In the schematic, nets do not have any built-in connection or property related to the test point tools in Expedition.
In Expedition, you can access this functionality with the net.RequiredNumberOfTestPoints of the MGCPCB.Net object.
There are many possible ways you could create a link to the schematic via your own automation, such as the creation of a text file you store in the design at the time of forward annotation. Such a text file could be read by an automation tool running with Expedition, and this function used to modify the value for each net.