Does not ignore SIGWINCH if no terminal is allocated

[waldiTM]

In src/libcrun/container.c exists a handler for SIGWINCH. This handler breaks out of the wait loop prematurely if no terminal is assigned:

                  if (UNLIKELY (args->terminal_fd < 0))
                    return 0;

As SIGWINCH can be sent at any time, this causes the whole container to be killed of if the terminal the crun process runs in is resized. As this signal is not critical, all failures in this handler should be ignored and not lead to killed containers.