In production mode, eager loading is enabled, and Devise is configured
by default to reload routes before eager loading. However, in
`config/application.rb` we also attempted to reload routes, which added
another 5-10 seconds of delay. In development mode, eager loading is
disabled, so we don't see this extra overhead.

To speed boot times, we only reload the routes if eager loading is
disabled.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/213992