res_pjsip_mwi: don't create mwi subscriptions if initial unsolicited disabled

If sending unsolicited mwi to all endpoints on startup is disabled
(mwi_disable_initial_unsolicited=yes) do not need to create subscriptions.
If there are many (thousands) realtime endpoints configured with unsolicited mwi
and Vociemail Storage configured as ODBC or IMAP there will be huge number of
DB/IMAP requests on startup.

ASTERISK-26230 #close

Change-Id: I50ae909639e3ee298b931a54def4b2b9e0fb86c5

res/res_pjsip_mwi.c

@@ -1278,7 +1278,9 @@ static struct ast_sorcery_observer global_observer = {
 
 static int reload(void)
 {
-	create_mwi_subscriptions();
+	if (!ast_sip_get_mwi_disable_initial_unsolicited()) {
+		create_mwi_subscriptions();
+	}
 	return 0;
 }
 
@@ -1301,13 +1303,13 @@ static int load_module(void)
 		ast_sip_unregister_subscription_handler(&mwi_handler);
 		return AST_MODULE_LOAD_DECLINE;
 	}
-	create_mwi_subscriptions();
 
 	ast_sorcery_observer_add(ast_sip_get_sorcery(), "contact", &mwi_contact_observer);
 	ast_sorcery_observer_add(ast_sip_get_sorcery(), "global", &global_observer);
 	ast_sorcery_reload_object(ast_sip_get_sorcery(), "global");
 
 	if (!ast_sip_get_mwi_disable_initial_unsolicited()) {
+		create_mwi_subscriptions();
 		if (ast_test_flag(&ast_options, AST_OPT_FLAG_FULLY_BOOTED)) {
 			ast_sip_push_task(NULL, send_initial_notify_all, NULL);
 		} else {