Fixed Mystic robe set reqs

What have you done in this MR?

Fixed #750 (closed) set the requirements of mystic robe equipment to be 20 def / 40 mage.

All variants included.

'09 source of robe reqs

Are there any tricky things testers should keep an eye out for?

• No

• Yes, as follows:

• I have tested these changes thoroughly.

• This requires extra testing due to changes to architecture or other similarly risky changes.

• I used the Thanos Tool for any JSON edits, I did not edit any JSON files by hand (MR will be rejected if there are manual JSON edits).

• I acknowledge that this contribution will be released under the AGPL license.