[202205] [timer.unit.j2] use wanted-by in timer unit (#2561)

- What I did
I fixed the timer unit template to account "wanted-by" option in the manifest. In case service is delayed, "wanted-by" is applied to the timer unit that delays it.

- How I did it
I updated timer.unit.j2 template

- How to verify it
Make sure that "WantedBy" is rendered in the timer unit.

Signed-off-by: Stepan Blyschak <stepanb@nvidia.com>

sonic-utilities-data/templates/timer.unit.j2

@@ -13,3 +13,7 @@ Unit={{ manifest.service.name }}{% if multi_instance %}@%i{% endif %}.service
 
 [Install]
 WantedBy=timers.target sonic.target
+{%- for service in manifest.service["wanted-by"] %}
+WantedBy={{ service }}{% if multi_instance and service in multi_instance_services %}@%i{% endif %}.service
+{%- endfor %}
+