Bug 34719: Add middle_name to patron autocomplete

Bug 34719: Add middle_name to patron autocomplete

To test:
1. Apply patch and clear browser cache.
2. Find some patrons with middle_name populated or add new patrons with a middle_name.
3. Make sure PatronAutoComplete is on
4. Try searching for a part of one of the patron's names who has a middle_name.
5. It should appear in the autocomplete dropdown

Signed-off-by: Matt Blenkinsop <matt.blenkinsop@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit a6c77f664c6b21b3d7c9ee4590a8b8b21a18a9b2)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>