swap recvfrom_into() port byte-order

[anecdata]

Addresses UDP server issue #4445 by changing the recvfrom_into() port number into network byte-order, so that sendto() replies back to the correct port that a client initiated the transaction from.

Successful sequence:

CircuitPython socketpool UDP Server:

code.py output:
Connecting to Wifi
Self IP 192.168.6.198
Server ping 192.168.6.198 0.0 ms
Create UDP Server socket ('192.168.6.198', 5000)

CPython UDP Client:

Create UDP Client Socket
Sent 12 bytes

tcpdump:

20:15:52.771675 IP: (tos 0x0, ttl 64, id 63564, offset 0, flags [none], proto UDP (17), length 40, bad cksum 0 (->f541)!)
    192.168.5.32.61409 > 192.168.6.198.5000: UDP, length 12

CircuitPython socketpool UDP Server:

Received bytearray(b'Hello, world') 12 bytes from ('192.168.5.32', 61409)
Sent bytearray(b'Hello, world') 12 bytes to ('192.168.5.32', 61409)

tcpdump:

20:15:52.885491 IP: (tos 0x0, ttl 255, id 233, offset 0, flags [none], proto UDP (17), length 40)
    192.168.6.198.5000 > 192.168.5.32.61409: UDP, length 12

CPython UDP Client:

Received bytearray(b'Hello, world') 12 bytes from ('192.168.6.198', 5000)

[anecdata]

Regression tested with this repo's NTP example, and with all supported combinations of CPython, CircuitPython ESP32SPI, and CircuitPython native (esp32s2) TCP and UDP clients and servers.

[hierophect]

Great! Thanks for fixing this!