Fix typedef

Author: andrjohns

stan/math/prim/fun/vector_seq_view.hpp

@@ -12,8 +12,9 @@ using is_matrix_or_std_vector
   = math::disjunction<is_matrix<T>, is_std_vector<T>>;
 
 template <typename T>
-using is_scalar_container = math::conjunction<is_matrix_or_std_vector<T>,
-                                              is_stan_scalar<value_type_t<T>>>;
+using is_scalar_container = math::disjunction<
+  is_matrix<T>,
+  math::conjunction<is_std_vector<T>, is_stan_scalar<value_type_t<T>>>>;
 }
 
 /**