src: allow unique_ptrs with custom deleter in memory tracker

Originally landed in the QUIC repo

Original review metadata:

```
  PR-URL: nodejs/quic#145
  Reviewed-By: James M Snell <[email protected]>
```

PR-URL: #31870
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: David Carlier <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Denys Otrishko <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>

Author: addaleax

src/memory_tracker-inl.h

@@ -99,9 +99,9 @@ void MemoryTracker::TrackField(const char* edge_name,
   }
 }
 
-template <typename T>
+template <typename T, typename D>
 void MemoryTracker::TrackField(const char* edge_name,
-                               const std::unique_ptr<T>& value,
+                               const std::unique_ptr<T, D>& value,
                                const char* node_name) {
   if (value.get() == nullptr) {
     return;

src/memory_tracker.h

@@ -134,9 +134,9 @@ class MemoryTracker {
                                  size_t size,
                                  const char* node_name = nullptr);
   // Shortcut to extract the underlying object out of the smart pointer
-  template <typename T>
+  template <typename T, typename D>
   inline void TrackField(const char* edge_name,
-                         const std::unique_ptr<T>& value,
+                         const std::unique_ptr<T, D>& value,
                          const char* node_name = nullptr);
 
   // For containers, the elements will be graphed as grandchildren nodes