Fix patient viewset distinct issue

[rithviknishad]

Proposed Changes

• Select DISTINCT ON the requested ordering field if present else select distinct on id.
• Reference: https://docs.djangoproject.com/en/5.0/ref/models/querysets/#django.db.models.query.QuerySet.distinct

Associated Issue

• Fixes ProgrammingError: SELECT DISTINCT ON expressions must match initial ORDER BY expressions #1952

Architecture changes

• Remove this section if not used

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

@coronasafe/care-backend-maintainers @coronasafe/care-backend-admins

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 62.17%. Comparing base (7c85464) to head (2ce91ec).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1953      +/-   ##
==========================================
+ Coverage   62.14%   62.17%   +0.03%     
==========================================
  Files         221      221              
  Lines       12198    12198              
  Branches     1740     1740              
==========================================
+ Hits         7580     7584       +4     
+ Misses       4310     4307       -3     
+ Partials      308      307       -1     

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