Bug 27827: make the 'Authority type:' input field wider

Bug 27827: make the 'Authority type:' input field wider

When adding a new authority type in the Staff client, the 'Authority type'
input field is too narrow. If you enter something like "OOP_CORPUS" inside
the textbox, you will have to scroll right and left inside the textbox in
order to view its contents.

This patch fixes that.

Test plan:
1) Try to add a new authority type with name "OOP_CORPUS". Notice how
   the input field is too narrow and cannot contain the entire string.
2) Apply this patch.
3) Repeat step 1), this time the input field has been widened and can
   accommodate the entire string.

Signed-off-by: Petro Vashchuk <stalkernoid@gmail.com>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>