res_pjsip: Only invoke unidentified endpoint logic when unidentified.

The code was incorrectly invoking the unidentified logic when
an endpoint had actually been identified, causing log messages
to be output.

ASTERISK-26349 #close

Change-Id: Id8104fc9e3d138d5e8b6f6977ecc08765fd17d4f

res/res_pjsip/pjsip_distributor.c

@@ -583,7 +583,7 @@ static pj_bool_t endpoint_lookup(pjsip_rx_data *rdata)
 
 	rdata->endpt_info.mod_data[endpoint_mod.id] = endpoint;
 
-	if (!is_ack) {
+	if ((endpoint == artificial_endpoint) && !is_ack) {
 		char name[AST_UUID_STR_LEN] = "";
 		pjsip_uri *from = rdata->msg_info.from->uri;