Conjunction and Disjunction queries always return invalid query error

When performing a FTS Conjunction, Disjunction, or boolean query the query fails with invalid query error. The reason for this is that our signature is mapQueriesToPs(...Query) but we then use it like mustQueries, err := i.mapQueriesToPs(q.data.Must.conjuncts) which means that we are actually effectively passing [][]Query and so the mapQueryToPs function fails.