FIX: Send assignment message in the notified user's locale

FIX: Send assignment message in the notified user’s locale

diff --git a/lib/topic_assigner.rb b/lib/topic_assigner.rb
index d48bfa0..563fbed 100644
--- a/lib/topic_assigner.rb
+++ b/lib/topic_assigner.rb
@@ -214,7 +214,11 @@ class ::TopicAssigner
         post: first_post,
         username: @assigned_by.username,
         notification_type: Notification.types[:custom],
-        excerpt: I18n.t("discourse_assign.topic_assigned_excerpt", title: @topic.title)
+        excerpt: I18n.t(
+          "discourse_assign.topic_assigned_excerpt",
+          title: @topic.title,
+          locale: assign_to.effective_locale
+        )
       )
     end

GitHub sha: 6d44f4fe