Fixes #3763

[brimoor]

Resolves #3763

Fixes a bug with:

dataset.merge_samples(samples, key_field=key_field, ...)

when dataset is a grouped dataset, samples is a list of samples, and a key_field is provided.

[codecov]

Codecov Report

Attention: 1646 lines in your changes are missing coverage. Please review.

Comparison is base (e0e6505) 15.57% compared to head (609d333) 15.41%.
Report is 25 commits behind head on develop.

Files	Patch %	Lines
...rc/components/ColorModal/controls/IdxColorList.tsx	0.00%	262 Missing ⚠️
app/packages/core/src/components/Starter/index.tsx	0.00%	243 Missing ⚠️
...nents/ColorModal/colorPalette/FieldsMaskTarget.tsx	0.00%	95 Missing ⚠️
...nts/ColorModal/colorPalette/DefaultMaskTargets.tsx	0.00%	92 Missing ⚠️
.../src/plugins/SchemaIO/components/LazyFieldView.tsx	0.00%	92 Missing ⚠️
...es/core/src/components/ColorModal/FieldSetting.tsx	0.00%	83 Missing ⚠️
app/packages/core/src/components/Common/Input.tsx	0.00%	83 Missing ⚠️
...pp/packages/core/src/components/Starter/content.ts	0.00%	75 Missing ⚠️
app/packages/operators/src/state.ts	0.00%	70 Missing ⚠️
app/packages/operators/src/hooks.ts	0.00%	69 Missing ⚠️
... and 32 more

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3816      +/-   ##
===========================================
- Coverage    15.57%   15.41%   -0.17%     
===========================================
  Files          645      657      +12     
  Lines        74120    75560    +1440     
  Branches       990     1000      +10     
===========================================
+ Hits         11542    11644     +102     
- Misses       62578    63916    +1338     

Flag	Coverage Δ
app	15.41% <6.05%> (-0.17%)	⬇️

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[swheaton]

lgtm and works as expected in the original issue.