Prevent `{ internal: true }` from being stored in the router

Forgotten followup to #23669 :grimacing:

If you went to an internal route (e.g. `/rails/info/routes`), you would
previously see the following in your logger:

```bash
Processing by Rails::InfoController#routes as HTML
  Parameters: {"internal"=>true}
  Rendering /Users/jon/code/rails/rails/railties/lib/rails/templates/rails/info/routes.html.erb within layouts/application
  Rendered collection of /Users/jon/code/rails/rails/actionpack/lib/action_dispatch/middleware/templates/routes/_route.html.erb [2 times] (10.5ms)
  Rendered /Users/jon/code/rails/rails/actionpack/lib/action_dispatch/middleware/templates/routes/_table.html.erb (2.5ms)
  Rendered /Users/jon/code/rails/rails/railties/lib/rails/templates/rails/info/routes.html.erb within layouts/application (23.5ms)
Completed 200 OK in 50ms (Views: 35.1ms | ActiveRecord: 0.0ms)
```

Now, with this change, you would see:

```bash
Processing by Rails::InfoController#routes as HTML
  Rendering /Users/jon/code/rails/rails/railties/lib/rails/templates/rails/info/routes.html.erb within layouts/application
  Rendered collection of /Users/jon/code/rails/rails/actionpack/lib/action_dispatch/middleware/templates/routes/_route.html.erb [2 times] (1.6ms)
  Rendered /Users/jon/code/rails/rails/actionpack/lib/action_dispatch/middleware/templates/routes/_table.html.erb (10.2ms)
  Rendered /Users/jon/code/rails/rails/railties/lib/rails/templates/rails/info/routes.html.erb within layouts/application (17.4ms)
Completed 200 OK in 44ms (Views: 28.0ms | ActiveRecord: 0.0ms)
```

1 files changed, 6 insertions, 0 deletions

diff --git a/railties/test/rails_info_controller_test.rb b/railties/test/rails_info_controller_test.rb
index c51503c2b7..2e10d63599 100644
--- a/railties/test/rails_info_controller_test.rb
+++ b/railties/test/rails_info_controller_test.rb
@@ -78,4 +78,10 @@ class InfoControllerTest < ActionController::TestCase
     get :routes, params: { path: 'rails/info/routes.html' }
     assert fuzzy_count.call == 0, 'should match optional parts of route literally'
   end
+
+  test "internal routes do not have a default params[:internal] value" do
+    get :properties
+    assert_response :success
+    assert_nil @controller.params[:internal]
+  end
 end