Fix PredicateBuilder::ArrayHandler so that it uses the correct Arel pred...

...icate when given a nested array

Fixes #16580

PredicateBuilder::ArrayHandler was using the incorrect Arel predicate (Arel::Nodes::Equality) when given a nested array. This fix restores the behavior on 4.1 stable and will utilize Arel::Nodes::In when given a nested array.
I could go either way. I chose this because the issue specifically called out malformed SQL.