bug: fix incorrect default config definitions for chart legends

[ClementTsang]

Description

A description of the change, what it does, and why it was made. If relevant (such as any change that modifies the UI), please provide screenshots of the changes:

I had changed how this was parsed in-code but I forgot to update the default configs. This also adds some e2e tests to hopefully catch this all for real in the future, since the schema ones don't catch this stuff and the constants test doesn't actually run the binary for a proper e2e test.

Issue

If applicable, what issue does this address?

From a discussion in #1592

Testing

If relevant, please state how this was tested. All changes must be tested to work:

If this is a code change, please also indicate which platforms were tested:

• Windows
• macOS
• Linux

Checklist

If relevant, ensure the following have been met:

• Areas your change affects have been linted using rustfmt (cargo fmt)
• The change has been tested and doesn't appear to cause any unintended breakage
• Documentation has been added/updated if needed (README.md, help menu, doc pages, etc.)
• The pull request passes the provided CI pipeline
• There are no merge conflicts
• If relevant, new tests were added (don't worry too much about coverage)

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 54.51%. Comparing base (3edf430) to head (b368e7f).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/options.rs	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1594      +/-   ##
==========================================
- Coverage   54.53%   54.51%   -0.02%     
==========================================
  Files         114      114              
  Lines       17672    17672              
==========================================
- Hits         9637     9634       -3     
- Misses       8035     8038       +3     

Flag	Coverage Δ
macos-12	37.27% <0.00%> (ø)
ubuntu-latest	56.93% <0.00%> (-0.02%)	⬇️
windows-2019	37.22% <0.00%> (ø)

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