feature(api, robot-server): add get command errors to runs router

[TamarZanzouri]

Overview

closes https://opentrons.atlassian.net/browse/EXEC-504.
add an end point in runs router to fetch commands error list.

Test Plan and Hands on Testing

• Post a protocol that will cause a recovery workflow.
• Start the run and let the command fail.
• Resume from recovery.
• Let the run end.
• GET /runs/{runId}/commandErrors and make sure you are getting the full command error list.

Changelog

• added an end point to commands router /runs/{runId}/commandErrors.
• added logic in CommandsState to get_error_slice.

Review requests

naming makes sense? changes make sense? location for the new route makes sense? (under commands router)

Risk assessment

low. adding new logic

[SyntaxColoring]

I think we should change the route from /commands/errors to /commandErrors, but other than that, this looks good to me. Thank you!

[sfoster1]

Some implementation notes, but mostly request-changes because of the route - I agree with @SyntaxColoring, I think this should be a child of /runs/:runid directly. I support /runs/:runid/errors rather than /runs/:runid/commandErrors just because it's shorter and I hate camelcase but obviously that's a matter of taste more than anything else.

[sfoster1]

Much nicer, love the new API presentation. I think we probably still want to hoist the cursor defaulting to the robot server but other than that I'm happy with it.

[SyntaxColoring]

I think the return type needs adjusting, but other than that this looks great, thanks.

[SyntaxColoring]

Looks good, thanks!