Bug 35101: Stop screen from jumping back to top when using barcode.pl plugin

To test:
1. Set 'autoBarcode' to something other than 'don't generate automatically'
2. If the a framwwork make sure some 952 fields have the barcode.pl plugin enabled
3. Add a new item and click the '...' next to the 952 field with the barcode.pl plugin enabled.
4. The screen jumps back to the top, annoying.
5. Apply patch
6. Try again, it should not jump anymore!

Signed-off-by: Barbara Johnson <barbara.johnson@swbell.net>
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit eec5d7e4be)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit 85d38e5ef5)
Signed-off-by: Matt Blenkinsop <matt.blenkinsop@ptfs-europe.com>

cataloguing/value_builder/barcode.pl

@@ -92,10 +92,12 @@ $scr
 
 function Focus$function_name(event) {
     set_barcode(event.data.id, false);
+    return false;
 }
 
 function Click$function_name(event) {
     set_barcode(event.data.id, true);
+    return false;
 }
 </script>
 END_OF_JS