Fix sign in token and warning emails failed to send in some cases

[helloworldstack]

When Setting.site_contact_email was incorrectly set with an invalid value such as - it could cause sign in token email failed to send with some SMTP providers such as Amazon SES because of invalid Reply-To. This also affect warning email on the same app/mailers/user_mailer.rb file.

Example error in Sidekiq Jobs

UserMailer#sign_in_token
Net::SMTPFatalError: 554 Transaction failed: Missing final '@domain'

Generally Setting.site_contact_email value should not have any effects on the ability to send sign in token or warning emails (UserMailer.sign_in_token and UserMailer.warning functions). Therefore reply_to field should use the global SMTP_REPLY_TO variable (#11718) instead based on config/environments/production.rb.