Bug 35554: Authority search popup width 800px

Bug 35554: Authority search popup width 800px

Authority search popup is only 700 pixels width.
Most popups use 800 pixels, like the z3950 one.

Test plan :
1) Edit a biblio record
2) Click on value builder in a field linked to authority (ie 700)
3) Check popup is 800 pixels wide
4) Same with advanced editor

Signed-off-by: Anneli Österman <anneli.osterman@koha-suomi.fi>
Signed-off-by: Pedro Amorim <pedro.amorim@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>