Test patches

[jcapriot]

Summary

Fixes a few small testing errors on main.

PR Checklist

• If this is a work in progress PR, set as a Draft PR
• Linted my code according to the style guides.
• Added tests to verify changes to the code.
• Added necessary documentation to any new functions/classes following the
  expect style.
• Added relevant method tags (i.e. GRAV, EM, etc.)
• Marked as ready for review (ff this is was a draft PR), and converted
  to a Pull Request
• Tagged @simpeg/simpeg-developers when ready for review.

Reference issue

What does this implement/fix?

Additional information

[codecov]

Codecov Report

Merging #1251 (11ea431) into main (96dddbd) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1251      +/-   ##
==========================================
+ Coverage   82.29%   82.31%   +0.01%     
==========================================
  Files         164      164              
  Lines       24967    24965       -2     
==========================================
+ Hits        20546    20549       +3     
+ Misses       4421     4416       -5     

Impacted Files	Coverage Δ
SimPEG/electromagnetics/time_domain/simulation.py	93.73% <ø> (+1.04%)	⬆️