refactor(api): only ignore stalls for downward portion of force pickup routine

[caila-marashaj]

Overview

During force tip-pickup, the z stage ignores stalls for all parts of the movement, including when it retracts back up towards the home position. This is believed to be the cause of some 'unknown position' problems popping in testing, so this changes the code to only ignore stalls during the parts of the routine that are actually pushing into the tiprack.

Changelog

• make ignoring stalls during the pickup routine conditional on the direction of movement
• change the target_down variable to target for readability purposes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.19%. Comparing base (8f50b08) to head (0ae7ba3).
Report is 54 commits behind head on edge.

❗ Current head 0ae7ba3 differs from pull request most recent head ae3eb1f. Consider uploading reports for the commit ae3eb1f to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             edge   #14725      +/-   ##
==========================================
- Coverage   67.50%   67.19%   -0.32%     
==========================================
  Files        2521     2495      -26     
  Lines       72090    71563     -527     
  Branches     9311     9076     -235     
==========================================
- Hits        48666    48088     -578     
- Misses      21228    21330     +102     
+ Partials     2196     2145      -51     

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

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Files	Coverage Δ
api/src/opentrons/hardware_control/ot3api.py	79.55% <ø> (ø)

... and 126 files with indirect coverage changes

[ahiuchingau]

Nice - LGTM once tested on the FLEX!

[sfoster1]

Okay, good once tested on a flex