LibWeb/HTML: Implement DataTransferItem.webkitGetAsEntry()

Author: https://github.com/jamierocks
Commit: 2e9aec984c
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1172
Reviewed-by: https://github.com/trflynn89

Userland/Libraries/LibWeb/HTML/DataTransferItem.idl

@@ -1,3 +1,4 @@
+#import <EntriesAPI/FileSystemEntry.idl>
 #import <FileAPI/File.idl>
 
 callback FunctionStringCallback = undefined (DOMString data);
@@ -9,4 +10,7 @@ interface DataTransferItem {
     readonly attribute DOMString type;
     undefined getAsString(FunctionStringCallback? _callback);
     File? getAsFile();
+
+    // https://wicg.github.io/entries-api/#dom-datatransferitem-webkitgetasentry
+    FileSystemEntry? webkitGetAsEntry();
 };