Bug 28033: Fix minor capitalization errors

Bug 28033: Fix minor capitalization errors

This patch corrects capitalization in two templates:

- Administration -> Desks:
  "Modify Desk" / "New Desk" -> "Modify desk", "New desk" in breadcrumbs
  menu.
- Reports -> Most-circulated items:
  "Most-circulated Items" -> "Most-circulated items" in breadcrumbs.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>