Core/GameObject: regenerate GO loot if respawn time passed since last loot generation time and not all items were taken (#19101)

src/server/game/Entities/GameObject/GameObject.cpp

@@ -60,6 +60,7 @@ GameObject::GameObject() : WorldObject(false), MapObject(),
     m_lootRecipientGroup = 0;
     m_groupLootTimer = 0;
     lootingGroupLowGUID = 0;
+    m_lootGenerationTime = 0;
 
     ResetLootMode(); // restore default loot mode
     m_stationaryPosition.Relocate(0.0f, 0.0f, 0.0f, 0.0f);