erp5_json_editor: Always drop the default

  Like it is done for option, remove default from schema after append the value into decription.
11 jobs for erp5-vifib in 0 seconds
Status Job ID Name Coverage
  External
failed ERP5.UnitTest-erp5-vifib

12:02:17

failed SlapOS-Master.UnitTest-Master

05:33:11

failed ERP5.UnitTest-erp5-vifib

04:15:12

failed ERP5.UnitTest-erp5-vifib

04:03:27

failed SlapOS-Master.UnitTest-Master

02:27:30

passed SlapOS-Master.UnitTest-Master

02:22:40

failed SlapOS-Master.UnitTest-Master

02:43:19

failed SlapOS-Master.UnitTest-Master

02:15:21

passed SlapOS-Master.UnitTest-Master

02:38:49

failed SlapOS-Master.UnitTest-Master

03:36:39

failed SlapOS-Master.UnitTest-Master

08:06:53