Multiple publishers and contributors not handled for DublinCore metadata

[ahmdthr]

Description

If there are multiple publishers or contributors, the request for DublinCore metadata crashes from GeoNode.
#1070

Environment

• operating system:
• Python version: 3.11
• pycsw version: 3.0
• source/distribution
  • git clone
  • DebianGIS/UbuntuGIS
  • PyPI
  • zip/tar.gz
  • other (please specify):
• web server
  • Apache/mod_wsgi
  • CGI
  • other (please specify): GeoNode

Steps to Reproduce

• Request for DublinCore metadata from GeoNode where the dataset has more than one publishers.
• The request fails.

Additional Information