manager: also restart stub listner on reload

Previously, the extra stub listners were stopped but new ones were not
started. Also, the main stub listners were not restarted, hence the
new settings were not applied. This fixes the above two issues.

Note, to fix the issue, we need to keep CAP_NET_BIND_SERVICE capability
to make it allow to bind stub listner later.

Fixes #37843.

src/resolve/resolved-manager.c

@@ -653,6 +653,7 @@ static int manager_dispatch_reload_signal(sd_event_source *s, const struct signa
         dns_server_unlink_on_reload(m->dns_servers);
         dns_server_unlink_on_reload(m->fallback_dns_servers);
         m->dns_extra_stub_listeners = ordered_set_free(m->dns_extra_stub_listeners);
+        manager_dns_stub_stop(m);
         dnssd_service_clear_on_reload(m->dnssd_services);
         m->unicast_scope = dns_scope_free(m->unicast_scope);
         m->delegates = hashmap_free(m->delegates);
@@ -691,6 +692,10 @@ static int manager_dispatch_reload_signal(sd_event_source *s, const struct signa
         manager_flush_caches(m, LOG_INFO);
         manager_verify_all(m);
 
+        r = manager_dns_stub_start(m);
+        if (r < 0)
+                return sd_event_exit(sd_event_source_get_event(s), r);
+
         (void) sd_notify(/* unset_environment= */ false, NOTIFY_READY_MESSAGE);
         return 0;
 }