ggml-cuda: check for srcs outside the cgraph (#18583)

* ggml-cuda: check for srcs outside the cgraph

* review: use leafs instead

ggml/src/ggml-cuda/common.cuh

@@ -1065,6 +1065,7 @@ struct ggml_cuda_graph {
     int number_consecutive_updates = 0;
     bool cuda_graphs_enabled = false;
     std::vector<ggml_graph_node_properties> ggml_graph_properties;
+    std::vector<ggml_graph_node_properties> extraneous_srcs_properties;
 #endif
 };