Firing the parts cannon can be a very expensive way f fixing things. It may well be a height sensor problem but after replacing it the suspension has to be calibrated.I didn't check if the spring was leaking, just assumed it was and changed it, when that didn't work , I thought it must be the height sensor, so I changed that and it seemed to work, but this morning its down on that side again
Diagnostics would be my suggestion. Replacing the strut made no difference so I would say that the original fault was not a leak.Sounds like its time to get out the spray bottle of soapy water and check the pipes and connections.