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, 1 insertions, 1 deletions

diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 8ff3b42a40..40b6500553 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -106,7 +106,7 @@ module ActionDispatch
           @ast                = ast
           @anchor             = anchor
           @via                = via
-          @internal           = options[:internal]
+          @internal           = options.delete(:internal)
 
           path_params = ast.find_all(&:symbol?).map(&:to_sym)