Shouldn't calls that time out raise errors?

If I’m understanding the Python sockets [docs](https://docs.python.org/3/library/socket.html#socket.timeout) correctly, a socket with timeout enabled should raise an error. But `recv()`, at least, just [returns](https://github.com/adafruit/Adafruit_CircuitPython_Wiznet5k/blob/f3070a3ecf91ffeee56bc4e23fbcec15ea071839/adafruit_wiznet5k/adafruit_wiznet5k_socket.py#L501) an empty byte object on timeout.

Start in adafruit_wiznet5k/adafruit_wiznet5k_socket.py at the recv() implementation linked in the issue, then compare its timeout behavior with Python's socket.timeout documentation. Confirm the expected behavior for a timed-out call and add or update coverage so the implementation reports the expected result.

Written by the indexing model from the issue text.