[Bug] Item Purchase Offset when multiple buyers are buying at the same time. (#4628)

* [Bug] Item Purchase Offset when multiple buyers are buying at the same time.

- Much of the code lifted from TAKP/P2002 and adapted
- Needs Testing
- This should help prevent situations where multiple people are purchasing items from a merchant and both attempt to purchase the same temp merchant or limited item, it should result in the later person recieving a notice that the item no longer exists and refreshes the merchant table.
- Updated strings

* fix formatting

* Push

* Update client.cpp

* Update database_update_manifest.cpp

* Update database_update_manifest.cpp

* Update database_update_manifest.cpp

* Update client.cpp

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Co-authored-by: Kinglykrab <kinglykrab@gmail.com>
Co-authored-by: Akkadius <akkadius1@gmail.com>

zone/client.h

@@ -1828,6 +1828,8 @@ public:
 
 	uint32 trapid; //ID of trap player has triggered. This is cleared when the player leaves the trap's radius, or it despawns.
 
+	void SendMerchantEnd();
+
 	Raid *p_raid_instance;
 
 	inline uint32 GetPotionBeltItemIcon(uint8 slot_id)