[Cleanup] Set GetAugmentType() to int again (#3335)

# Notes
- Augment type can be `-1` for all augment types.

zone/lua_iteminst.cpp

@@ -70,7 +70,7 @@ bool Lua_ItemInst::IsAugmentable() {
 	return self->IsAugmentable();
 }
 
-uint32 Lua_ItemInst::GetAugmentType() {
+int Lua_ItemInst::GetAugmentType() {
 	Lua_Safe_Call_Int();
 	return self->GetAugmentType();
 }

zone/lua_iteminst.h

@@ -40,7 +40,7 @@ public:
 	bool IsEquipable(int race, int class_);
 	bool IsEquipable(int slot_id);
 	bool IsAugmentable();
-	uint32 GetAugmentType();
+	int GetAugmentType();
 	bool IsExpendable();
 	Lua_ItemInst GetItem(int slot);
 	Lua_Item GetItem();