LG-5847: Update confirmation email language

[jc-gsa]

🎫 Ticket

LG-5847

🛠 Summary of changes

To reproduce:

• Register a new account but do not confirm the account, note the language selected
• Register an account using the same email address as before and change the language preference
• Notice that the second email arrives in the desired language

[aduth]

LGTM 👍

[aduth]

I was curious if ActiveRecord was smart enough to avoid a database query if the value is unchanged, and based on some quick testing in a Rails console, it seems like it is? Keeping it as-is is fine too if the condition helps make it more explicit.

[2] pry(main)> u.email_language
=> "en"
[3] pry(main)> u.update(email_language: 'en')
=> true
[4] pry(main)> u.update(email_language: 'fr')
  TRANSACTION (0.5ms)  BEGIN
  User Update (3.0ms)  UPDATE "users" SET "updated_at" = $1, "email_language" = $2 WHERE "users"."id" = $3  [["updated_at", "2023-03-28 12:55:15.383464"], ["email_language", "fr"], ["id", 22]]
  TRANSACTION (2.1ms)  COMMIT
=> true

Suggested change

	if existing_user.email_language != email_language
	existing_user.update(email_language: email_language)
	end
	existing_user.update(email_language: email_language)