refactor(api): Remove failed command state

[SyntaxColoring]

Overview

This goes towards EXEC-301.

This removes this piece of internal Protocol Engine state:

opentrons/api/src/opentrons/protocol_engine/state/commands.py

Lines 155 to 156 in 7689521

	failed_command: Optional[CommandEntry]
	"""The command, if any, that made the run fail and the index in the command list."""

It's only used as a pagination helper for robot-server, and it's sort of semantically problematic in a world where a run has many failed commands and none of them are necessarily fatal.

Test Plan

To do.

Changelog

To do.

Review requests

To do.

Risk assessment

To do.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (nonfatal_errors_refactors@5f024d9). Click here to learn what that means.

Additional details and impacted files

@@                     Coverage Diff                      @@
##             nonfatal_errors_refactors   #14664   +/-   ##
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  Coverage                             ?   67.33%           
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  Files                                ?     2485           
  Lines                                ?    71416           
  Branches                             ?     9057           
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  Hits                                 ?    48091           
  Misses                               ?    21173           
  Partials                             ?     2152           

Flag	Coverage Δ
g-code-testing	92.43% <ø> (?)

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Files	Coverage Δ
...pi/src/opentrons/protocol_engine/state/commands.py	99.36% <ø> (ø)
robot-server/robot_server/commands/router.py	100.00% <ø> (ø)
...server/robot_server/runs/router/commands_router.py	100.00% <ø> (ø)

[SyntaxColoring]

Closing for now: this tempts us down a robot-server pagination rabbithole that doesn't seem productive right now. I'll go with a different approach that doesn't involve removing this piece of state.