AK: Zero previous pointer *after* fixing the insertion list in HashTable

Author: https://github.com/Hendiadyoin1
Commit: 5bf84a5b0e
Pull-request: https://github.com/SerenityOS/serenity/pull/14363
Reviewed-by: https://github.com/IdanHo

AK/HashTable.h

@@ -704,11 +704,11 @@ private:
                 bucket.previous->next = bucket.next;
             else
                 m_collection_data.head = bucket.next;
-            bucket.previous = nullptr;
             if (bucket.next)
                 bucket.next->previous = bucket.previous;
             else
                 m_collection_data.tail = bucket.previous;
+            bucket.previous = nullptr;
             bucket.next = nullptr;
         }
     }