fix: Change error handling to return default Vertex for unknown node …

…types in graph class

src/backend/base/langflow/graph/graph/base.py

@@ -1422,7 +1422,7 @@ def _get_vertex_class(self, node_type: str, node_base_type: str, node_id: str) -
 
         if node_type in lazy_load_vertex_dict.VERTEX_TYPE_MAP:
             return lazy_load_vertex_dict.VERTEX_TYPE_MAP[node_type]
-        raise ValueError(f"Vertex type {node_type} not found")
+        return Vertex
 
     def _build_vertices(self) -> List["Vertex"]:
         """Builds the vertices of the graph."""