pulse-server: also remove creating objects

When an object is created, it is marked creating until all roundtrips
complete. If the object is removed in between, we don't remove it
because find_object does not return creating objects.

Make find_object also return the creating objects to fix this.

src/modules/module-protocol-pulse/manager.c

@@ -165,8 +165,6 @@ static struct object *find_object(struct manager *m, uint32_t id)
 {
 	struct object *o;
 	spa_list_for_each(o, &m->this.object_list, this.link) {
-		if (o->this.creating)
-			continue;
 		if (o->this.id == id)
 			return o;
 	}