According to MC-136112 it is intended that /forceload can not be run from functions or command blocks because of how much damage could be done with it.

However /forceload query only delivers information but can't be run either.
It could however be useful to at least know if a chunk is forceloaded or not, be it just for debugging reasons or to notify the server owner of missing forceloaded areas they need to re-add to keep a datapack working.

_{I would also argue that datapacks can only be installed by the server owner to begin with and that there is commands that can do worse damage than /forceload.}