Remove multiselectfield references

[sainak]

Proposed Changes

• convert references in migrations to CharField
• remove references from code
• remove multiselectfield package
• tested migrations on a fresh db
• closes Remove multiselectfield references from migrations and other places #2216
• closes Remove package django-multiselect-field #2213

Merge Checklist

• Tests added/fixed
• Update docs in /docs
• Linting Complete
• Any other necessary step

Only PR's with test cases included and passing lint and test pipelines will be reviewed

@ohcnetwork/care-backend-maintainers @ohcnetwork/care-backend-admins

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.24%. Comparing base (4f6296a) to head (ed7ee06).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2444      +/-   ##
===========================================
+ Coverage    64.20%   64.24%   +0.04%     
===========================================
  Files          240      240              
  Lines        13562    13544      -18     
  Branches      1947     1942       -5     
===========================================
- Hits          8707     8702       -5     
+ Misses        4496     4484      -12     
+ Partials       359      358       -1     

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