Huh, didn't know about this. I just edited my save file. Add farmmana in mansionupgrades after farmhatchery.
"mansionupgrades":{"farmcapacity":3,"farmhatchery":0,"farmmana":0,"farmtreatment":1,"foodcapacity":2,"foodpreservation":0,"jailcapacity":8,"jailincenses":1,"jailtreatment":1,"mansionalchemy":2,"mansionbed":3,"mansioncommunal":20,"mansionkennels":1,"mansionlab":2,"mansionlibrary":3,"mansionluxury":2,"mansionnursery":1,"mansionparlor":1,"mansionpersonal":10}