Bug 19706: (QA follow-up) Hide the collection code selector if no value is defined...

Bug 19706: (QA follow-up) Hide the collection code selector if no value is defined (for consistency)

Test plan:
0) Go to item search
1) Do have some authorized values in CCODE category -> selector of
collection is visible
2) Don't have any authorized value in CCODE category -> selector of
collection is not visible

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>