Activate sentry for counter journal client

Related to T3662

Test Plan

octo-diff:

$SWH_PUPPET_ENVIRONMENT_HOME/bin/octocatalog-diff --octocatalog-diff-args --no-truncate-details --to staging counters0
...
*******************************************
  File[/etc/systemd/system/swh-counters-journal-client.service] =>
   parameters =>
     content =>
      @@ -8,4 +8,7 @@
      _
       [Service]
      +Environment=SWH_SENTRY_DSN=https://swh::deploy::counters::sentry_token@sentry.softwareheritage.org/19
      +Environment=SWH_SENTRY_ENVIRONMENT=staging
      +Environment=SWH_MAIN_PACKAGE=swh.counters
       User=swhstorage
       Group=swhstorage
*******************************************
  Systemd::Unit_file[swh-counters-journal-client.service] =>
   parameters =>
     content =>
      @@ -8,4 +8,7 @@
      _
       [Service]
      +Environment=SWH_SENTRY_DSN=https://swh::deploy::counters::sentry_token@sentry.softwareheritage.org/19
      +Environment=SWH_SENTRY_ENVIRONMENT=staging
      +Environment=SWH_MAIN_PACKAGE=swh.counters
       User=swhstorage
       Group=swhstorage
*******************************************
*** End octocatalog-diff on counters0.internal.staging.swh.network

---

Migrated from D6478 (view on Phabricator)