If present, the "originalMetadataAuthor" node should be set to default user

XWiki 14.0 introduced a new document property originalMetadataAuthor. This property was added to the XAR format, then removed in 14.5. When present in the XML, this property needs to be set to the GitLab config default user otherwise the XAR plugin verifier will report an error.

References:

• https://forum.xwiki.org/t/make-xar-format-remove-the-new-originalmetadataauthor-element/10435
• https://extensions.xwiki.org/xwiki/bin/view/Extension/XAR%20Module%20Specifications