remove legacy Blacklight::Utils check
remove legacy Blacklight::Utils check

following instructions here:
https://github.com/projectblacklight/blacklight/wiki/Update-to-Blacklight-7.0.1

Blacklight::Utils is removed, and this `needs_attr_accessible` check is for
legacy Rails support. it's not needed anymore.

samvera/hyrax,samvera/hyrax,samvera/hyrax,samvera/hyrax