When forwarding emails into the group inbox, we now use the
original sender email as the from_address since
2ac9fd9dff. However, we have not
been saving the original CC addresses of the forwarded email,
which are needed to include those recipients in on the conversation
when replying via the group inbox.
This commit captures the CC addresses on the incoming email, and
makes sure the emails are created as staged users and added to the
list of topic allowed users so they are included on CC's sent by
the GroupSmtpEmail and other jobs.
When 2ac9fd9dff was done, this
affected the small post that is created when forwarding an email
into the group inbox. Instead of using the name and the email of
the user who forwarded the email, it used the original from email
and name to create the small post. So instead of something like
"Discourse Team forwarded the above email" we ended up with
"John Smith forwarded the above email" which is incorrect.
This fixes the issue by creating a staged user for the forwarding
email address (if such a user does not yet exist) and uses that
for the "forwarded" small post instead.
Martin Brennan