fix custom op attr names size error (#44938)

paddle/fluid/pybind/eager_functions.cc

@@ -333,8 +333,7 @@ static std::vector<paddle::any> CastAttrsToTragetType(
                         src.size()));
   for (size_t i = 0; i < src.size(); i++) {
     size_t end = attrs_names[i].find(": ");
-    std::string type_name =
-        attrs_names[i].substr(end + 2, attrs_names.size() - end - 2);
+    std::string type_name = attrs_names[i].substr(end + 2);
     if (type_name == "int") {
       if (src[i].type() == typeid(bool)) {
         res.emplace_back(static_cast<int>(paddle::any_cast<bool>(src[i])));