fix(flex-stacker): clear ack message cache when a stall is detected.

[vegano1]

Overview

This fixes an issue where the ack cache would get full when a stall occurred because the incoming move message was not getting the expected response. So let's clear the ack cache when we get a stall before we send an error message.

Testing

• Trigger multiple stalls and make sure we no longer get gcode cache full messages

[sfoster1]

Looks good I think. This means that the python side is expected to cancel its tracking of any in-flight moves when it gets a stall, right?

[ahiuchingau]

Nice

[vegano1]

Looks good I think. This means that the python side is expected to cancel its tracking of any in-flight moves when it gets a stall, right?

yeah that's correct.