LibWeb: Remove unused DataTransfer-related IDL factories

The IDL for DataTransferItem and DataTransferItemList do not have
constructors.

Userland/Libraries/LibWeb/HTML/DataTransferItem.cpp

@@ -13,11 +13,6 @@ namespace Web::HTML {
 
 JS_DEFINE_ALLOCATOR(DataTransferItem);
 
-JS::NonnullGCPtr<DataTransferItem> DataTransferItem::construct_impl(JS::Realm& realm)
-{
-    return realm.heap().allocate<DataTransferItem>(realm, realm);
-}
-
 DataTransferItem::DataTransferItem(JS::Realm& realm)
     : PlatformObject(realm)
 {

Userland/Libraries/LibWeb/HTML/DataTransferItem.h

@@ -17,7 +17,6 @@ class DataTransferItem : public Bindings::PlatformObject {
     JS_DECLARE_ALLOCATOR(DataTransferItem);
 
 public:
-    static JS::NonnullGCPtr<DataTransferItem> construct_impl(JS::Realm&);
     virtual ~DataTransferItem() override;
 
 private:

Userland/Libraries/LibWeb/HTML/DataTransferItemList.cpp

@@ -13,11 +13,6 @@ namespace Web::HTML {
 
 JS_DEFINE_ALLOCATOR(DataTransferItemList);
 
-JS::NonnullGCPtr<DataTransferItemList> DataTransferItemList::construct_impl(JS::Realm& realm)
-{
-    return realm.heap().allocate<DataTransferItemList>(realm, realm);
-}
-
 DataTransferItemList::DataTransferItemList(JS::Realm& realm)
     : PlatformObject(realm)
 {

Userland/Libraries/LibWeb/HTML/DataTransferItemList.h

@@ -17,7 +17,6 @@ class DataTransferItemList : public Bindings::PlatformObject {
     JS_DECLARE_ALLOCATOR(DataTransferItemList);
 
 public:
-    static JS::NonnullGCPtr<DataTransferItemList> construct_impl(JS::Realm&);
     virtual ~DataTransferItemList() override;
 
 private: