Fix: private messages split into two windows over WeeChat's IRC relay

When you send a private message, ZoiteChat sometimes gets the same
message echoed back by the server so it can show it in the right
window. Whether it recognizes that echo depended on the server first
confirming a feature called "echo-message" during connection setup.

WeeChat's relay doesn't seem to confirm that feature the way other
servers (or ZNC) do, so ZoiteChat didn't recognize its own echoed
messages and treated them as brand new incoming messages from
yourself, opening a second, separate conversation window instead of
using the one you were already typing in.

This makes ZoiteChat recognize its own message by checking who sent
it, instead of only trusting that feature confirmation. That way,
sent and received messages always end up in the same conversation
window, regardless of how well the server/relay announces its
capabilities.

src/common/proto-irc.c

@@ -1368,7 +1368,7 @@ process_named_msg (session *sess, char *type, char *word[], char *word_eol[],
 						{
 							if (ignore_check (word[1], IG_PRIV))
 								return;
-							if (serv->have_echo_message && !serv->p_cmp (nick, serv->nick))
+							if (!serv->p_cmp (nick, serv->nick))
 							{
 								session *target_sess = find_dialog (serv, to);