CP Minimqtt: possible issue with connect() retry always throwing an exception after one failed attempt

For full details, please see this Forum thread:
https://forums.adafruit.com/viewtopic.php?p=1083496#p1083496

Short version:
Note that _reconnect_attempts_max value is initialized by the constructor to 5, from by the default value for connect_retries.

Start with the Forum thread linked in the issue and trace connect() retry behavior, especially how the constructor initializes _reconnect_attempts_max from connect_retries. Reproduce the reported case where one failed attempt causes an exception, then verify that retry behavior matches the configured maximum.

Written by the indexing model from the issue text.