Fix _has then chain then _has searches

[lukedegruchy]

• Fix the Has predicate to properly handle a chain within a_has that references a _has. So for coverage.payor._has:List:item:_id it was effectively ignoring the payor part of the chain, skipping to _has:List:item:_id when it should have processed payor._has:List:item:_id instead, skipping a level of recursion and building incorrect SQL that was missing a JOIN and referencing the wrong resource type.
• Add several new tests for various search strings containing combinations of _has and chains.

Closes: #5756

[github-actions]

Formatting check succeeded!

[epeartree]

Approved upon changes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.38%. Comparing base (497b9f2) to head (d7386d8).
Report is 5 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5735      +/-   ##
============================================
- Coverage     83.39%   83.38%   -0.02%     
+ Complexity    26927    26923       -4     
============================================
  Files          1681     1681              
  Lines        103965   103986      +21     
  Branches      13189    13189              
============================================
+ Hits          86702    86704       +2     
- Misses        11613    11630      +17     
- Partials       5650     5652       +2     

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