Rather than returning the negative error value.
This is intended to close#7606, though I did not test with mqtt.
Instead, I created a simple standalone test program:
```python
import wifi, socketpool, ssl, time
#wifi.radio.connect(<omitted>)
import socketpool
socket = socketpool.SocketPool(wifi.radio)
ctx = ssl.create_default_context()
b = bytearray(8)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sss = ctx.wrap_socket(s, server_hostname='example.com')
sss.connect(('example.com', 443))
sss.setblocking(False)
r = sss.recv_into(b)
print(r, b) # prints 4294967285 which is -11 as unsigned
sss.close()
```
Before the change, r was the out of range value 4294967285. After the
change, the recv_into call raises OSError instead.
This is comparable to the behavior on standard Python, though an
SSLWantReadError is raised instead.
The original (mis)behavior seems to match what was uncovered deep inside
minimqtt by adding logging:
```
370.578: DEBUG - PKT: _sock_exact_recv: recv_len = 4294967285
```
Watchdogs are used to reboot out of the bootloader. There is a
scratch register for user watchdogs. So use sdk functions to better
distinguish these.
Related to #7346
The comment says it is `buffer[start:end]` but it assumed elements
were a single byte long. Now it correctly does multibyte elements
from array.array.
Fixes#4988
Now, open wifi works on Pico W, so this closes#7438.
For the web workflow it's now OK to either
* specify an empty password string (as before)
* not have the CIRCUITPY_WIFI_PASSWORD key at all (new functionality)
reset_port calls reset_all_pins, which disables the built-in pull
down. In theory, this could allow some CYW43 interfacing pin to float
to an inappropriate value. There's no proof of this! but the move can't
really hurt, either
* read() is now readinto() and takes the buffer to write into.
* readinto() returns the number of valid samples.
* readinto() can be interrupted by ctrl-c.
* readinto() API doesn't support signed numbers because it never did.
* sample_rate is now required in the constructor because supported
values will vary per-port.
* 16 bit values are full range. 12 bit samples from RP2040 are stretched
in the same way they are for AnalogIn.
Fixes#7226
