Bug 37127: Authorized value select not working on authority forms

Bug 37127: Authorized value select not working on authority forms

Linking an authority subfield to an authorized value just leaves a blank
in the form rather than creating a <select>, because there's a stray cud-
in the type returned from build_authorized_values_list.

Test plan:
 1. Without the patch, Administration - Authority types - Actions menu for
    Default - MARC Structure
 2. Actions menu for 040 - Subfields
 3. Edit subfields - Tab b - Authorized value - set to LANG - Save changes
 4. Authorities - New authority - Default
 5. In 040 tag, click CATALOGING SOURCE to expand the tag
 6. Note that subfield b has a blank space rather than a dropdown menu
 7. Apply patch, restart_all
 8. Authorities - New authority - Default
 9. In 040 tag, click CATALOGING SOURCE to expand the tag
10. Note that subfield b has a dropdown menu listing language names

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Emily Lamancusa <emily.lamancusa@montgomerycountymd.gov>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>