Fix: fmt() methods applied to groupname_col

[juleswg23]

Summary

This PR ensures data for group labels in groupname_col are fetched from the formatted table values, rather than pure text. The example code in the linked issue now outputs:

One caveat is I don't know what the expected behavior should be with None/NA values in the groupname_col. This PR is specifically designed with the intention of not modifying the rendering of None/NA values.

Related GitHub Issues and PRs

Closes #236

Checklist

• I understand and agree to the Code of Conduct.
• I have followed the Style Guide for Python Code as best as possible for the submitted code.
• I have added pytest unit tests for any new functionality.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.44%. Comparing base (5196b53) to head (c402fc9).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #755   +/-   ##
=======================================
  Coverage   91.43%   91.44%           
=======================================
  Files          47       47           
  Lines        5547     5551    +4     
=======================================
+ Hits         5072     5076    +4     
  Misses        475      475           

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[juleswg23]

Instead of this PR, we can assign group_info.group_label to have formatted/relevant text for display. At the moment it is always None.

When that is done, group_label = group_info.defaulted_label() will get the correct label, and we won't have to implement this workaround.