Revert "Add ULS groups to an aggregate group"

This reverts commit 8d4e939d841f02685121aab9cfd4bccc4dd4e31b.

Tries to form aggregate group by combining messages from two
different namespaces, which does not work currently.

Change-Id: Ieef5c6a64f528bbff547d8e250a29896abb1ca82