Retries in sensitive steps

[fall-byrd]

I've noticed in a few spots that could be sensitive steps (dispensing reagents for example) we have retries around failure. For certain kinds of failures like hardware communication this could be fine but if it we end up with a partial application of a step with a retry I could see getting into a state that would call for a failure of the full recipe.

This all being said I know we're still getting things fully working so no one should be impacted by this but I wanted to highlight this for consideration well before then.

[phaseloop]

Also retry may actually dispense more than requested for some reason - for example if you miss "ack" from GRBL and it actually ran motors - on retry you will get double the reagent.

Better fail fast than kill someone, so AFAIK we have two options:

• on any serious error stop the process and that's it
• on any serious error stop the process and give the user option for example to manually dispense what's needed or left to dispense and hit "Continue".