Transfer Effect button only disappears after reopening item sheet

The transfer effects button does not disappear if no eligible effects are present due to changes to them while the item sheet is open.
Fix is rather labor intensive as it does not appear to simply rerender the header buttons

Start by tracing the item sheet's transfer effects button and how eligibility changes are propagated while the sheet remains open. The fix is complete when the button updates immediately and disappears when no eligible effects remain, without reopening the sheet.

Written by the indexing model from the issue text.