fix(api): use old TC Gen2 labwareOffset values in legacy core

[sanni-t]

Fixes issue in RESC-196

Overview

In this PR, we changed how we calculate the final origin of any labware placed on a TC gen2. Previously we assumed that all labware sit 98.26mm above the OT2 slot; we call it the TC labware offset. This offset was correct for the Armadillo plate; while other pcr plates would sit +/-0.1mm differently. In 7.0.1, we updated this labware offset to be the top plane of metal cylinders of the thermocycler (108.96mm), and introduced a stackingOffsetWithModule parameter in the labware definitions to inform us of the distance a labware actually rests at from top of those cylinders. For labware that didn’t have these offsets, we added a fallback of using the previous labware offset of 98.26.

Issue is, we forgot to add that fallback in v2.13, which is a legacy core based API so now the backend assumes all labware sit at 108.96mm on TC Gen2, ignoring any stackingOffsetWithModule because the legacy core has no concept of stacking offsets.

I compiled all this, with options for solutions in this spreadsheet and we decided to go with option 1- revert the behavior of API v2.13 to what it was prior to the change in 7.0.1.

Test Plan

• Load a TC Gen2 protocol on the OT2 without loading any previous LPC offsets and verify that pipettes go to the correct z height for the labware on the thermocycler, rather than moving 1cm above the labware.
• Also verify that TC gen1 nor any other modules are affected.

Changelog

• when loading module labware offsets in module geometry, it will now load separate, older offset values for TC gen2
• other minor code refactoring

Review requests

• Is it enough to save the older offsets in shared-data like that or do we want to have a better system for it?

Risk assessment

Medium. This adds/ reverts a change in positioning such that previous LPC offsets should not used or they'll result in pipettes crashing into labware bottom. We should also convey this to users.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (35a8b78) 68.24% compared to head (f162218) 68.12%.
Report is 21 commits behind head on edge.

Additional details and impacted files

@@            Coverage Diff             @@
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- Coverage   68.24%   68.12%   -0.12%     
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  Files        2514     2514              
  Lines       71865    72244     +379     
  Branches     9175     9307     +132     
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+ Hits        49041    49217     +176     
- Misses      20657    20843     +186     
- Partials     2167     2184      +17     

Flag	Coverage Δ
app	64.58% <ø> (-0.28%)	⬇️
g-code-testing	96.48% <ø> (ø)
protocol-designer	37.92% <ø> (-0.10%)	⬇️
shared-data	75.25% <100.00%> (+<0.01%)	⬆️
step-generation	86.90% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...ta/python/opentrons_shared_data/module/__init__.py	93.75% <100.00%> (+0.20%)	⬆️

... and 17 files with indirect coverage changes

[sfoster1]

Changes and cocnept LGTM