Previously, email addresses that weren't connected to a Zulip account
were ignored but now they receive an email stating their email isn't
connected to a Zulip account.
Also, removes the "Thanks for using Zulip!" line at the end of the
find accounts email that's sent when a Zulip account is found.
Updates the i18n test that used this string with another in the
German translation from this a successful account found email.
Fixes part of #3128
Co-authored-by: Lauryn Menard <lauryn@zulip.com>
Apparently, when we renamed these files to no longer have a .txt
extension, we accidentally removed them from the set of strings for
translation, because `manage.py makemessages` by default only
processes .txt and .html files under the templates/ directory.
Fix this by adding a .txt extension.
swayam0322
Eeshan Garg
Tim Abbott