Add SNAP integration tests from CBPP

[nmrodelo]

Adds tests from https://www.cbpp.org/research/food-assistance/a-quick-guide-to-snap-eligibility-and-benefits

This revealed issues, so it fixes #1155 and fixes #1156

[MaxGhenis]

Thanks, looks like these two issues will help us pass this test:

1. Add updated SNAP benefits for FY2022 #27 for 2022 parameters
2. SNAP childcare deduction #376 for the childcare deduction

I've bumped both up to sprint backlog.

[codecov]

Codecov Report

Merging #375 (3297925) into master (20f2735) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 3297925 differs from pull request most recent head c6fe561. Consider uploading reports for the commit c6fe561 to get more accurate results

@@           Coverage Diff           @@
##           master     #375   +/-   ##
=======================================
  Coverage   95.53%   95.53%           
=======================================
  Files         730      730           
  Lines       12899    12900    +1     
  Branches      936      937    +1     
=======================================
+ Hits        12323    12324    +1     
  Misses        540      540           
  Partials       36       36           

Impacted Files	Coverage Δ
.../deductions/shelter/snap_net_income_pre_shelter.py	100.00% <100.00%> (ø)

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