GUI: undo button is useless in declare attackers/blockers dialog

That's button restore to last permanent only, not to original state before selection started.

Current bugs:
* do not refresh GUI's selections after undo
* if you choose attackers/blockers one by one then that undo button will be useless -- it's rollback only last tap action;

Need research -- is it buggy or by design. Current human can click on permanent to select/deselect it, but single undo can be useful to restore after forced payment and other additional actions:
* `PayCostToAttackBlockEffect`

Possible solutions:
* fix selection bug
* fix rollback to original state, not single permanent

Start with the GUI declare attackers/blockers dialog and the PayCostToAttackBlockEffect path mentioned in the issue. Determine whether undo should restore the original selection or only the last permanent, and verify that GUI selections refresh after undo; done requires an agreed behavior and corresponding fix.

Written by the indexing model from the issue text.