lease not loaded from memfile if user context has multiple key-value pairs

memfile CSV:

address,hwaddr,client_id,valid_lifetime,expire,subnet_id,fqdn_fwd,fqdn_rev,hostname,state,user_context
10.0.0.1,ff:01:02:03:04:08,01:ff:01:02:03:04:08,7200,1641205200,1,0,0,,0,{"comment": "hello", "comment2": "do not release"}

error:

ERROR DHCPSRV_MEMFILE_LEASE_LOAD_ROW_ERROR discarding row x, error: EOF read, one of ",}" expected in <string>:y:z

See MemfileLeaseMgrTest.v4UserContext and MemfileLeaseMgrTest.v6UserContext unit tests. They will require adjustments.