Support filtering Joiner on BiConstraintStream

The following piece of code:

constraintFactory.fromUniquePair(..., Joiners.filtering(...))

throws an exception:

java.lang.IllegalArgumentException: The joiner class (class org.optaplanner.core.impl.score.stream.bi.FilteringBiJoiner) is not supported.

 While a similar constraint that uses a filter works correctly: 

constraintFactory.fromUniquePair(...).filter(...))

  Expected result:

The Joiner.filtering() should work the same was as the filter().