Debug intermittent testing failures

[nfahlgren]

Describe your changes
Changes aimed at debugging the cause of intermittent test failures where pytest exits with null code.

Type of update
Is this a: Work in progress

For the reviewer
See this page for instructions on how to review the pull request.

• PR functionality reviewed in a Jupyter Notebook
• All tests pass
• Test coverage remains 100%
• Documentation tested
• New documentation pages added to plantcv/mkdocs.yml
• Changes to function input/output signatures added to updating.md
• Code reviewed
• PR approved

[deepsource-io]

Here's the code health analysis summary for commits 142bf93..19129c4. 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%	100%

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[maliagehan]

added tests back one by one and found that the napari functions need to have viewer.close() after each test (even though the showviewer=false) for tests to run right on github actions, even though they consistently work locally.

[maliagehan]

repo continuous integration changed to decrease image size. Also found that we needed to add viewer.close() to tests even though viewer does close locally with no error consistently. Additional small changes were also made that were probably originally unnecessary when we were trying to troubleshoot building the repo. Actions now consistently run. Huzzah