fix: try avoiding use of SFINAE param in using

Author: henryiii

include/pybind11/pybind11.h

@@ -1969,7 +1969,7 @@ struct iterator_state {
 // iterators in the wild can't be dereferenced when const. C++ needs the extra parens in decltype.
 template <typename Iterator, typename ResultType = decltype((*std::declval<Iterator>()))>
 struct iterator_access {
-    using result_type = ResultType;
+    using result_type = decltype((*std::declval<Iterator>()));
     // NOLINTNEXTLINE(readability-const-return-type) // PR #3263
     result_type operator()(Iterator &it) const {
         return *it;
@@ -1978,15 +1978,15 @@ struct iterator_access {
 
 template <typename Iterator, typename ResultType = decltype(((*std::declval<Iterator>()).first)) >
 struct iterator_key_access {
-    using result_type = ResultType;
+    using result_type = decltype(((*std::declval<Iterator>()).first));
     result_type operator()(Iterator &it) const {
         return (*it).first;
     }
 };
 
 template <typename Iterator, typename ResultType = decltype(((*std::declval<Iterator>()).second))>
 struct iterator_value_access {
-    using result_type = ResultType;
+    using result_type = decltype(((*std::declval<Iterator>()).second));
     result_type operator()(Iterator &it) const {
         return (*it).second;
     }