Universal Viewer should default to displaying index tab on a generic show page with children to display #3527
Description
Descriptive summary
This issue was described in #2684 and fixed in #2689, however it appears that currently, the UV is back to loading initially with the thumbnails tab open and displaying the thumbnail of the first child.
Expected behavior
Given a generic item with child works (which in turn have file sets), when the generic's show page loads, UV should display the index of children in the left pane.