fix: validate every item of QuerySpec filterExpression

[ndr-brt]

What this PR changes/adds

Validate all the Criterion.filterExpression items instead of the first one only.

Why it does that

fix bug

Further notes

• improved the Criterion validation itself, the "rightOperand" must be considered mandatory as in the EDC there are no operators that permit an empty rightOperand
• some documentation added

Linked Issue(s)

Closes #3424

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[codecov-commenter]

Codecov Report

Patch coverage: 87.50% and project coverage change: +0.01% 🎉

Comparison is base (f981237) 72.09% compared to head (958dee7) 72.11%.

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3467      +/-   ##
==========================================
+ Coverage   72.09%   72.11%   +0.01%     
==========================================
  Files         836      836              
  Lines       16985    16987       +2     
  Branches      947      947              
==========================================
+ Hits        12246    12250       +4     
+ Misses       4335     4333       -2     
  Partials      404      404              

Files Changed	Coverage Δ
...alidator/jsonobject/validators/MandatoryValue.java	90.00% <0.00%> (-10.00%)	⬇️
.../edc/validator/jsonobject/JsonObjectValidator.java	100.00% <100.00%> (ø)
...sonobject/validators/model/CriterionValidator.java	88.88% <100.00%> (+0.65%)	⬆️
...sonobject/validators/model/QuerySpecValidator.java	92.85% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[paullatzelsperger]

LGTM