[Client] Fix crash when creating Cell from base Cell lacking Pathgrid

apps/openmw/mwmp/RecordHelper.cpp

@@ -373,10 +373,14 @@ void RecordHelper::overrideRecord(const mwmp::CellRecord& record)
         // Note: This has to be done after the new Cell has been created so the Pathgrid override
         //       can correctly determine whether the Cell is an interior or an exterior
         const ESM::Pathgrid* basePathgrid = world->getStore().get<ESM::Pathgrid>().search(record.baseId);
+
+        if (basePathgrid)
+        {
             ESM::Pathgrid finalPathgrid = *basePathgrid;
             finalPathgrid.mCell = recordData.mName;
             world->getModifiableStore().overrideRecord(finalPathgrid);
         }
+    }
     else
     {
         LOG_APPEND(TimedLog::LOG_INFO, "-- Ignoring record override with invalid baseId %s", record.baseId.c_str());