Add a missing translation for already_signed_out
Add a missing translation for already_signed_out

This translation seems to be missing. Copy over the string from
signed_out as in en.yml.

nikolai-b/devise-i18n,jyrkij/devise-i18n,humancopy/devise-i18n,tigrish/devise-i18n,mhlopko/devise-i18n,mabras/devise-i18n,tigrish/devise-i18n