bug(datasets): keychecker fails to check some wrong arguments

[tpoisot]

Closes #186

[github-actions]

Documentation for this PR at https://poisotlab.github.io/SpeciesDistributionToolkit.jl/previews/PR193/

[codecov-commenter]

Codecov Report

Patch coverage: 10.00% and project coverage change: +5.83 🎉

Comparison is base (385831f) 47.53% compared to head (b7ae751) 53.36%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #193      +/-   ##
==========================================
+ Coverage   47.53%   53.36%   +5.83%     
==========================================
  Files          47       59      +12     
  Lines        1378     1692     +314     
==========================================
+ Hits          655      903     +248     
- Misses        723      789      +66     

Flag	Coverage Δ
unittests	53.36% <10.00%> (+5.83%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
SimpleSDMDatasets/src/keychecker.jl	70.96% <10.00%> (ø)

... and 11 files with indirect coverage changes

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