Remove |callback| in favor of |error| + updated request

[scheibo]

There was discussion on #5370 about this, but #5370 (comment) discovered the existing error message is insufficent, and either making |error| structured or resending the updated request along with an |error| would be required to replace |callback|. If we resent the request with approriate information updated (ie. maybeTrapped -> trapped, etc), it would remove the need for RandomPlayerAI to have any state, at the cost of additional bandwidth usage in the error cases (expected to be negligible in terms of oveall bandwidth impact).