Issue 283 nano plot scaling

[minimav]

Summary

This PR fixes a bug whereby values from unselected rows affect the scaling in nanoplots. In addition to the single values case given in #283, a simple example of the bug in the context of multiple values per row is below (when autoscale is used):

multiple_vals_df = pd.DataFrame(
    {
        "i": list(range(1, 3)),
        "lines_small": ["12.44 6.34", "5.2 -8.2 10"],
        "lines_large": ["12.44, 6.34", "5.2 -8.2 100"],
    }
)
(
    GT(multiple_vals_df, rowname_col="i")
    .fmt_nanoplot(columns="lines_small", rows=[0], plot_type="line", autoscale=True)
    .fmt_nanoplot(columns="lines_large", rows=[0], plot_type="line", autoscale=True)
)

Single values example post-fix:

Multiple values example post-fix:

I have added a couple of unit tests based on existing ones, let me know if they work. Thanks for your work on this library, I have been using it at work and really enjoying it 🙂

Related GitHub Issues and PRs

• Ref: #283

Checklist

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

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 86.64%. Comparing base (f8e30ea) to head (f1df81e).

Files	Patch %	Lines
great_tables/_formats.py	83.33%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #404 +/- ## ========================================== + Coverage 86.40% 86.64% +0.24% ========================================== Files 42 42 Lines 4700 4704 +4 ========================================== + Hits 4061 4076 +15 + Misses 639 628 -11 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.