Revert "test-dhcp-client: add temporary workaround for assertion failure"

This reverts commit 1686c884bf.

The issue should be fixed by the previous commit. Let's drop the
workaround.

src/libsystemd-network/test-dhcp-client.c

@@ -522,9 +522,7 @@ static void test_addr_acq(sd_event *e) {
         res = sd_dhcp_client_start(client);
         assert_se(IN_SET(res, 0, -EINPROGRESS));
 
-        r = sd_event_loop(e);
-        /* Times out since https://github.com/systemd/systemd/issues/28990 add workaorund for now */
-        assert_se(r >= 0 || r == -ETIMEDOUT);
+        assert_se(sd_event_loop(e) >= 0);
 
         assert_se(sd_dhcp_client_set_callback(client, NULL, NULL) >= 0);
         assert_se(sd_dhcp_client_stop(client) >= 0);