Fix #4287: Hide Dmail notice persistently shown even after closing

app/views/users/_dmail_notice.html.erb

@@ -1,4 +1,4 @@
-<div class="notice notice-info notice-large" id="dmail-notice" data-id="<%= latest_unread_dmail(CurrentUser.user) %>">
+<div class="notice notice-info notice-large" id="dmail-notice" data-id="<%= latest_unread_dmail(CurrentUser.user).id %>">
   <h2>You have <%= link_to "unread mail", dmails_path(search: { folder: "received" }) %>.</h2>
   <div><%= link_to "Close this", "#", id: "hide-dmail-notice" %></div>
 </div>

test/functional/dmails_controller_test.rb

@@ -194,6 +194,15 @@ class DmailsControllerTest < ActionDispatch::IntegrationTest
         assert_select "#dmail-notice", 1
         assert_select "#nav-my-account-link", text: "My Account (1)"
       end
+
+      should "not show the unread dmail notice after closing it" do
+        cookies[:hide_dmail_notice] = @user.dmails.active.unread.first.id
+        get_auth posts_path, @user
+
+        assert_response :success
+        assert_select "#dmail-notice", 0
+        assert_select "#nav-my-account-link", text: "My Account (1)"
+      end
     end
   end
 end