Json2csv update: handle lists of coordinates

[HaleySchuhl]

Describe your changes
Adjust the json2csv utility function to handle lists of coordinates e.g. leaf tip coordinates from the morphology subpackage.

Type of update
Is this a:

• Bug fix (previously json2csv would run but would have squished syntax, and this bad syntax would throw an error while reading the resulting csv in with pandas as a dataframe)

• feature enhancement
• Work in progress

Associated issues

Additional context
Changes the formatting for coordinate-type outputs, where we have multi-value traits that are lists of points. Updated output format looks like this:

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Here's the code health analysis summary for commits c6105a7..f6d1944. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
Python	✅ Success		View Check ↗
Test coverage	✅ Success		View Check ↗

Code Coverage Report

Metric	Aggregate	Python
Branch Coverage	100%	100%
Composite Coverage	100%	100%
Line Coverage	100%	100%
New Branch Coverage	100%	100%
New Composite Coverage	100%	100%
New Line Coverage	100%, ✅ Above Threshold	100%, ✅ Above Threshold

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[HaleySchuhl]

Need to refine these updates for handling lists of coordinates. The changes so far resolve the fatal error when trying to read the csv output in Python with pandas but would require more data wrangling in R since the syntax [x y] is handled as a character dtype.

Refine based on the downstream use case, such as calculating distance matrices with leaf tip coordinates (for segment ID assignment between timepoints for example).

[HaleySchuhl]

Closing in favor of a different approach described in #1857