[FW][FIX] mail: correctly check all recipients when routing on aliases

/!\ This commit is a manual forward-port of two PR targetting originally
11.0: #40442 and its fix / partial revert #41042. /!\

Purpose of this commit is to check all recipients of incoming emails when
trying to determine the route to apply. Notably

  * an incoming email should be considered as a write to catchall only if all
    recipients are catchall. Catchall + a valid alias should take the alias
    into account;
  * an incoming email sent to the bounce alias should be considered as a bounce
    even if another valid alias is in recipients and whatever the order. Indeed
    it indicates an issue and bounce is considered as more important;
  * forward to an alias linked to another model should check all recipients
    and not only the first one. Otherwise reply_alias, forward_alias is
    considered as a reply whereas it should be considered as a forward when
    considering all recipients;

Tests are added according to those specifications.

Please see original PRs for more details about the content, the comments
done on it and the various discussions.

PR #46764
Task ID 2121551

X-original-commit: df00bd2d3bddf9a2b56e8554380669025e146d21

0 files changed, 0 insertions, 0 deletions