[PATCH 3/5] lib-smtp: smtp-server - Expose smtp_server_connection_reply_immediate

[PATCH 3/5] lib-smtp: smtp-server - Expose smtp_server_connection_reply_immediate

The function already existed internally as a way to write a reply directly
to the output stream, bypassing the per-command reply queue. Make it part
of the public API so callers that need a reply on the wire before tearing
the connection down (where queued replies would otherwise be aborted) can
use it.

Gbp-Pq: Name 0003-lib-smtp-smtp-server-Expose-smtp_server_connection_r.patch