Fix: move sms config to jh initializers fold

Related to !662 (merged)

What does this MR do and why?

This does not happen on production.

The jh/lib/jh/sms.rb is included in Rails autoload list and will be reloaded in development mode according to Rails autoloading doc, then the JH::Sms.config used in views will be reset to nil.

Rails.application.config.autoload_paths.grep /jh\/lib/
=> ["/Users/mtan/dev/jihu-gitlab/gitlab/jh/lib", "/Users/mtan/dev/jihu-gitlab/gitlab/jh/lib/generators"]

To fix this we need to:

• Move the jh/lib/jh/sms.rb to initializers fold to avoid the file reloading.

Screenshots or screen recordings

How to set up and validate locally

1. Goto {{YOUR_HOST}}/users/sign_up
2. You should see the phone area code drop list
3. Add a comment to a random file under /jh/lib/
4. Reload your browser
5. Then you should see this error

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.