Looks like there is no operator available for FieldRelation criterion.

Steps to reproduce:
1. Place the Command from attachment in src directory in metarepository.
2. Run php bin/console ezplatform:test:es

Expected:
I can filter the results using FieldRelation critetion

Actual:

In DispatcherVisitor.php line 35:

  Intentionally not implemented: No visitor available for: eZ\Publish\API\Repository\Values\Content\Query\Criterion\FieldRelation
   with operator in

The same thing happens with Operation::Contains, meaning there is no available operator for FieldRelation criterion