Restore diff test

[OliviaLynn]

Change Description

Restoring the diff test (looks like an old version was accidentally merged in)

Code Quality

• [x] I have read the Contribution Guide
• [x] My code follows the code style of this project
• [x] My code builds (or compiles) cleanly without any errors or warnings
• [x] My code contains relevant comments and necessary documentation

[codecov[bot]]

Codecov Report

Merging #135 (8bba572) into main (535565d) will decrease coverage by 0.02%. Report is 4 commits behind head on main. The diff coverage is 60.52%.

@@            Coverage Diff             @@
##             main     #135      +/-   ##
==========================================
- Coverage   74.82%   74.81%   -0.02%     
==========================================
  Files          27       27              
  Lines        2483     2474       -9     
==========================================
- Hits         1858     1851       -7     
+ Misses        625      623       -2     

Files Changed	Coverage Δ
src/superphot_plus/plotting/confusion_matrices.py	33.53% <35.71%> (-0.59%)	:arrow_down:
src/superphot_plus/plotting/classifier_results.py	60.29% <57.14%> (+0.06%)	:arrow_up:
src/superphot_plus/plotting/sampling_results.py	72.60% <60.00%> (-0.17%)	:arrow_down:
src/superphot_plus/utils.py	99.39% <80.00%> (-0.61%)	:arrow_down:
src/superphot_plus/mlp.py	100.00% <100.00%> (ø)
src/superphot_plus/plotting/lightcurves.py	95.45% <100.00%> (-0.06%)	:arrow_down:
src/superphot_plus/plotting/utils.py	84.93% <100.00%> (ø)
src/superphot_plus/samplers/numpyro_sampler.py	98.46% <100.00%> (ø)