[FIX]Fixed the issue of save selected fields list in export.
[MERGE] [FIX] export wizard: better behaviour when saving new fields list

- Show the fields list once we save the first one
- When delete a list, remove the selected fields
- When add a list, do not remove the selected fields
[MERGE] [FIX] export wizard: better behaviour when saving new fields list

- Show the fields list once we save the first one
- When delete a list, remove the selected fields
- When add a list, do not remove the selected fields