Uploading a file by drag-and-drop in the WYSIWYG editor doesn't honor the size limitation for attachments

Steps to reproduce:

• Define a small size limit for attachments following https://www.xwiki.org/xwiki/bin/view/Documentation/AdminGuide/Attachments#HSizeLimit
• Try to upload a file larger than the size limit by uploading it thanks to the attachment tab of any page were the user has edit rights. It will fail, as expected.
• Switch to edit mode in this page
• Drag and drop the same file in the page

Expected result: the upload is blocked

Actual result: the upload is successful and the link in the page created