[core] Dual Wield Setup

[Skold177]

I affirm:

• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Fixes a very rare edge case where a monster that has dual wield on setup never gets the flag cleared if its transformed to a different job that might not have dual wield on spawn.