Users can search on embargoed trees and matrices

Data that are not yet available to the public should not be searchable. This is working for Study ID 10381: if you search on study_id = 10381, you won't get any results. However, the matrices that belong to study 10381 are, in fact, searchable. For example, you can search on matrices 5123 and 5124, and you can search on trees 7581 and 7582. You can also search on the taxon "Melpomene firma", then click on the Trees tab and see that Tree 7582 is in the results set. Although it is true that if you try to download these trees and matrices, you can't do that -- it would be better if they did not even appear in the results set. Course, in adding this requirement that only non-embargoed data can be returned in the results of a query, we need to be cautious that this added search criterion does not sacrifice on performance. Once this is fixed in the interface, let's check that it's okay in the API.