Bug 36452: correct display of patron message

Bug 36452: correct display of patron message

To test:
1. Before applying the patch:
2. In the staff interface, navigate to a patron
3. Add a new staff message that contains multiple lines (e.g. using
   enter for the next line)
4. Save the message and check the display.
   It will be a single line.
5. Apply the patch and navigate back to the
   patron
6. The message should now be displayed as multiple lines.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 5e8059a6f83493149ecefc03b9a47c42288a26ee)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>