Fix missing parameter in MMQTTException

[Neradoc]

This fixes raising a MMQTTException with no argument, raising a TypeError, when it requires an error argument, as reported in #248

Traceback (most recent call last):
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 1036, in _wait_for_msg
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 1124, in _sock_exact_recv
  File "adafruit_esp32spi/adafruit_esp32spi_socketpool.py", line 171, in recv_into
  File "adafruit_esp32spi/adafruit_esp32spi_socketpool.py", line 198, in _available
  File "adafruit_esp32spi/adafruit_esp32spi.py", line 892, in socket_available
  File "adafruit_esp32spi/adafruit_esp32spi.py", line 431, in _send_command_get_response
  File "adafruit_esp32spi/adafruit_esp32spi.py", line 398, in _wait_response_cmd
  File "adafruit_esp32spi/adafruit_esp32spi.py", line 377, in _wait_spi_char
TimeoutError: Timed out waiting for SPI char

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "code.py", line 247, in <module>
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 1011, in loop
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 1041, in _wait_for_msg
TypeError: function takes 3 positional arguments but 2 were given

Code done running.

Notes that: raise MMQTTException is equivalent to raise MMQTTException()

It should now be (didn't test)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "code.py", line 247, in <module>
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 1011, in loop
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 1041, in _wait_for_msg
MMQTTException: Unexpected error while waiting for messages

Code done running.

[dglaude]

I confirm that this kind of change fixed the problem for me.

I used this for a few hours and the problem did not reoccur (or I was able to catch the exception and retry):

raise MMQTTException("Please insert meaningfull message here.") from error

I don't know what should be the right string, but @Neradoc version is certainly better than mine.