Fix API Sanitizing MSONable types in combined types

[shyamd]

This should fix the issue where MSONable types in a combined type such as Union and Dict were not being properly sanitized for the API.

[codecov]

Codecov Report

Merging #454 (fc970c1) into main (09ac770) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #454      +/-   ##
==========================================
+ Coverage   88.21%   88.24%   +0.03%     
==========================================
  Files          40       40              
  Lines        2604     2611       +7     
==========================================
+ Hits         2297     2304       +7     
  Misses        307      307              

Impacted Files	Coverage Δ
src/maggma/api/query_operator/sparse_fields.py	97.05% <ø> (ø)
src/maggma/core/store.py	86.27% <ø> (ø)
src/maggma/api/API.py	80.48% <100.00%> (ø)
src/maggma/api/query_operator/__init__.py	100.00% <100.00%> (ø)
src/maggma/api/query_operator/dynamic.py	94.28% <100.00%> (-0.09%)	⬇️
src/maggma/api/query_operator/pagination.py	88.88% <100.00%> (ø)
src/maggma/api/query_operator/sorting.py	83.33% <100.00%> (ø)
src/maggma/api/query_operator/submission.py	95.45% <100.00%> (ø)
src/maggma/api/resource/__init__.py	100.00% <100.00%> (ø)
src/maggma/api/resource/aggregation.py	94.28% <100.00%> (ø)
... and 7 more

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