[Performance] Improvements to ScanCloseMobs logic (#4534)

* [Performance] Minor improvements to ScanCloseMobs

* Remove timer checks one level up to reduce branching

* Reserve memory in m_close_mobs to avoid frequent re-allocations if not already reserved.

zone/mob.h

@@ -1488,7 +1488,6 @@ public:
 
 	bool IsCloseToBanker();
 
-	void ScanCloseMobProcess();
 	std::unordered_map<uint16, Mob *> &GetCloseMobList(float distance = 0.0f);
 	void CheckScanCloseMobsMovingTimer();