Merge pull request #12372 from ZehMatt/path-underflow-warnings

Fix GetAdditionEntry trying obtain the object when no additions exist

src/openrct2/world/Footpath.cpp

@@ -1529,6 +1529,8 @@ ObjectEntryIndex PathElement::GetAdditionEntryIndex() const
 
 rct_scenery_entry* PathElement::GetAdditionEntry() const
 {
+    if (!HasAddition())
+        return nullptr;
     return get_footpath_item_entry(GetAdditionEntryIndex());
 }