Copying embedded draft file links to another context can result in 'file does not exist' error

Since MDL-62037, when multiple files with the same filename are uploaded a 'time' parameter is added to the download link. Since MDL-45170 (added in 3.6), when text containing a draftfile.php link is copied to another context, the files are parsed and duplicated into the new context. Any links with the time parameter fail to parse correctly causing a 'file not found' error to be displayed.

Steps to replicate:

• Add new content to course (e.g. label)
• Insert the multiple images using the file picker (select overwrite on subsequent upload)
• Select and copy content from the editor
• Save and return to course
• Add another content item (e.g. label)
• Paste copied content
• Save and return to course
• 'File does not exist' error is displayed

A potential fix included in the referenced patch is to update the filename regex in the extract_draft_file_urls_from_text function so parameters are excluded (by way of excluding '?' character from valid filename chars).