chore: mark conversation notifications as read on visit (#13906)

app/services/notification/mark_conversation_read_service.rb

@@ -0,0 +1,25 @@
+class Notification::MarkConversationReadService
+  pattr_initialize [:user!, :account!, :conversation!]
+
+  def perform
+    return unless user.is_a?(User)
+
+    notifications.find_each do |notification|
+      notification.update!(read_at: read_at)
+    end
+  end
+
+  private
+
+  def notifications
+    user.notifications.where(
+      account: account,
+      primary_actor: conversation,
+      read_at: nil
+    )
+  end
+
+  def read_at
+    @read_at ||= Time.current
+  end
+end