Bug 24264: Use raw field when limiting by authtype

Bug 24264: Use raw field when limiting by authtype

To test:
1 - Have a genre form record in your authorities file
2 - Search authorities for 'Default'
3 - The result is returned
4 - Set the dropdown to 'Genre/Form' and search matchign term
5 - No results
6 - Apply patch
7 - Restart all the things
8 - Repeat search for 'Genre/Form' and search matching term
9 - Record is returned

Signed-off-by: Myka Kennedy Stephens <mkstephens@lancasterseminary.edu>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>