[services] Update "WantedBy=" section for tacacs-config.timer. (#11893)

The timer execution may fail if triggered during a config reload
(when the sonic.target is stopped). This might happen in a rare
situation if config reload is executed after reboot in a small
time slot (for 0 to 30 seconds) before the tacacs-config timer
is triggered. To ensure that timer execution will be resumed after
a config reload the WantedBy section of the systemd service is updated
to describe relation to sonic.target.

Signed-off-by: Oleksandr Ivantsiv <oivantsiv@nvidia.com>

Signed-off-by: Oleksandr Ivantsiv <oivantsiv@nvidia.com>

files/build_templates/tacacs-config.timer

@@ -9,4 +9,4 @@ OnBootSec=5min 30 sec
 Unit=tacacs-config.service
 
 [Install]
-WantedBy=timers.target updategraph.service
+WantedBy=timers.target sonic.target sonic-delayed.target