Fix SFINAE bug in container base type

This commit fixes a bug in the use of SFINAE in the container base type.
In particuler, this issue has three layers:

1. The existing code uses the `typename = std::enable_if` anti-pattern
   which is discouraged in the C++ standard.
2. The code used `std::enable_if` without getting `::type` from it,
   meaning that a specialization failure cannot ever occur, rendering
   the SFINAE useless.
3. The check used about type equality is incorrect, it should rather
   check constructability.

This commit fixes the issues by converting the code to a C++20 requires
clause and by modifying the conditions.

Author: stephenswat

core/include/traccc/edm/details/container_base.hpp

@@ -137,13 +137,11 @@ class container_base {
     /**
      * @brief Constructor from a pair of "view type" objects
      */
-    template <typename header_vector_tp, typename item_vector_tp,
-              typename = std::enable_if<
-                  std::is_same<header_vector_tp, header_vector>::value>,
-              typename = std::enable_if<
-                  std::is_same<item_vector_tp, item_vector>::value>>
-    TRACCC_HOST_DEVICE container_base(const header_vector_tp& hv,
-                                      const item_vector_tp& iv)
+    template <typename header_vector_tp, typename item_vector_tp>
+    requires(std::constructible_from<header_vector, const header_vector_tp&>&&
+                 std::constructible_from<item_vector, const item_vector_tp&>)
+        TRACCC_HOST_DEVICE
+        container_base(const header_vector_tp& hv, const item_vector_tp& iv)
         : m_headers(hv), m_items(iv) {
 
         assert(m_headers.size() == m_items.size());