So wall clock time formats less likely display a one-off value,
duration formats are too rarely used if the expected duration is
less than 24 hours.

Change-Id: I9b0872420699b17e3ed3f20993f8cfe02761f862
Reviewed-on: https://gerrit.libreoffice.org/71909
Tested-by: Jenkins
Reviewed-by: Eike Rathke <erack@redhat.com>