systemctl: make list-timers not say "left" in "LEFT" column

systemctl: make list-timers not say "left" in "LEFT" column

We would print:
NEXT                        LEFT          LAST                        PASSED        UNIT                           >
Wed 2023-02-22 23:55:00 CET 20min left    Wed 2023-02-22 23:25:00 CET 9min ago      pmlogger_check.timer           >
Wed 2023-02-22 23:55:10 CET 21min left    Wed 2023-02-22 23:25:16 CET 8min ago      pmlogger_farm_check.timer      >
Wed 2023-02-22 23:58:00 CET 23min left    Wed 2023-02-22 23:28:02 CET 6min ago      pmie_check.timer               >
Wed 2023-02-22 23:58:10 CET 24min left    Wed 2023-02-22 23:28:11 CET 5min ago      pmie_farm_check.timer          >
Thu 2023-02-23 00:00:00 CET 25min left    Wed 2023-02-22 00:00:10 CET 23h ago       logrotate.timer                >
Thu 2023-02-23 00:00:00 CET 25min left    Wed 2023-02-22 00:00:10 CET 23h ago       unbound-anchor.timer           >
Thu 2023-02-23 00:08:00 CET 33min left    Wed 2023-02-22 00:08:05 CET 23h ago       pmie_daily.timer               >
Thu 2023-02-23 00:10:00 CET 35min left    Wed 2023-02-22 00:10:03 CET 23h ago       pmlogger_daily.timer           >
Thu 2023-02-23 00:14:14 CET 40min left    Wed 2023-02-22 22:35:09 CET 58min ago     dnf-makecache.timer            >
Thu 2023-02-23 05:05:04 CET 5h 30min left Wed 2023-02-22 03:29:00 CET 20h ago       plocate-updatedb.timer         >
Thu 2023-02-23 11:34:34 CET 12h left      Wed 2023-02-22 11:34:33 CET 11h ago       systemd-tmpfiles-clean.timer   >
Sun 2023-02-26 01:00:00 CET 3 days left   Mon 2023-02-20 07:51:59 CET 2 days ago    raid-check.timer               >
Mon 2023-02-27 00:19:48 CET 4 days left   Mon 2023-02-20 07:51:59 CET 2 days ago    fstrim.timer                   >
Mon 2023-02-27 12:34:36 CET 4 days left   Tue 2023-02-21 08:22:14 CET 1 day 15h ago archlinux-keyring-wkd-sync.time>

The "left" part uses precious screen estate and is pretty much implied
by the column name. Drop it.