Yet another quadtree runtime fix

[Drulikar]

About the pull request

This PR is a follow up to #11099 where I see another runtime where a weakref is missing in the quadtree. What this should mean is that the mob was qdeleted when the quadtrees fired thus preventing a weakref from being returned when calling WEAKREF; but since right now our quadtrees monitors clients, its not like its necessarily incorrect that a client could have a deleted mob...

Explain why it's good for the game

Should fix

Testing Photographs and Procedure

Will just monitor runtimes in the future after merge.

Changelog

:cl: Drathek fix: Fixed an edgecase where quadtree results would fail because a qdeleted mob was in the tree /:cl: