Avoid event listeners leak

[Luluno01]

Bug Description

If somehow the server won't respond to an in-game item query (via inspectItem), there will be a inspectItem#<item-id> event listener leak.

If you send the inspect requests too frequently or send invalid requests, the server will ignore some of the requests, i.e. the server may never respond to some specific requests. This will cause a event listener leak until the same item is finally "inspected" again successfully.