Query: Preserve selector for Count/LongCount

[smitpatel]

Currently we remove the selector for queries involving Count/LongCount. This helps us in running query even if it has client evaluation.
But in cases of group by we may need to do count over particular property to avoid issues like #27130 So we should preserve selector for such cases. We could apply this initially for queries which are on grouping element only. We would throw if we fail to translate selector for those cases in #27130