Export: Content export fails with embedded image URI:s

Description

EPiServer CMS 8.8 data export fails if there are any embedded images using Data URI scheme (starting with, "data:image/png;base64,...").

Steps to reproduce

1. Create a page with XHtmlString property and open TinyMCE rich editor.
2. Click Insert/Edit Image button
3. Copy data from text document in attachments and paste in Image URL field
4. Try to export this page

Expected: Preferably content exported with images, otherwise wanrning displayedabout embedded images after export.

Actual: Failed to export property MainBody, exception: Invalid URI: The Uri string is too long.