res_pjsip_session: Restore calls to ast_sip_message_apply_transport()

Commit 44bb0858cb ("debugging: Add enough
to choke a mule") accidentally removed calls to
ast_sip_message_apply_transport when it was attempting to just add
debugging code.

The kiss of death was saying that there were no functional changes in
the commit comment.

This makes outbound calls that use the 'flow' transport mechanism fail,
since this call is used to relay headers into the outbound INVITE
requests.

ASTERISK-29124 #close

Change-Id: I0f3e32c2e8ac415e30b1d29966d75a1546f0526a

res/res_pjsip_session.c

@@ -4388,6 +4388,8 @@ static void handle_outgoing_request(struct ast_sip_session *session, pjsip_tx_da
 	SCOPE_ENTER(3, "%s: Method is %.*s\n", ast_sip_session_get_name(session),
 		(int) pj_strlen(&req.method.name), pj_strbuf(&req.method.name));
 
+	ast_sip_message_apply_transport(session->endpoint->transport, tdata);
+
 	AST_LIST_TRAVERSE(&session->supplements, supplement, next) {
 		if (supplement->outgoing_request && does_method_match(&req.method.name, supplement->method)) {
 			supplement->outgoing_request(session, tdata);
@@ -4412,6 +4414,8 @@ static void handle_outgoing_response(struct ast_sip_session *session, pjsip_tx_d
 			ast_sip_session_get_name(session));
 	}
 
+	ast_sip_message_apply_transport(session->endpoint->transport, tdata);
+
 	AST_LIST_TRAVERSE(&session->supplements, supplement, next) {
 		if (supplement->outgoing_response && does_method_match(&cseq->method.name, supplement->method)) {
 			supplement->outgoing_response(session, tdata);