espressif: Validate sample rate

[jepler]

The reported code used an invalid sample rate. This improves the error message so that it is not a generic IDFError.

The new error message says:

ValueError: sample_rate must be 20000-2000000

I verified at a sample rate of 20000 that I could read both 0 and 65535 using a jumper wire to another GPIO pin configured as a digital output.

My test code, run on a feather esp32 v2:

import digitalio, board, analogbufio, array

N = 30
rate = 20000

buffer = array.array("H", [0x0000] * N)
with digitalio.DigitalInOut(board.MISO) as d, analogbufio.BufferedIn(board.A3, sample_rate=rate) as adc:
    for v in (0, 1):
        d.switch_to_output(v)
        adc.readinto(buffer)
        for i in range(N):
            print(i, buffer[i])

Closes #9504

[jepler]

(the rate range is a bit different for each microcontroller, so esp32s3 for instance might display a different range in its error message)

[tannewt]

Thank you!

[graeme-winter]

Yes thank you for the fix 👍