fix(service): start drs-sensor after ptp4l to ensure time sync readiness (#147)

Add ptp4l.service to the After= directive of drs-sensor.service so the
sensor driver does not start before the PTP daemon is running. Without
this ordering, the Seyond LiDAR driver floods logs with PTP clock sync
errors ("failed to step clock: Invalid argument").

Author: otenim

ansible/roles/drs_sensor_service/templates/drs-sensor.service.jinja2

@@ -1,7 +1,7 @@
 [Unit]
 Description=DRS Launch Service
 Requires=network-online.target systemd-modules-load.service
-After=network-online.target cyclonedds-local.service systemd-modules-load.service
+After=network-online.target cyclonedds-local.service systemd-modules-load.service ptp4l.service
 
 [Service]
 Type=exec