Cannot select groupHeader row(s) with gridApi.selection.selectRow

[troywoy]

The gridApi.selection.selectRow API method searches for an entity in the flatgridOptions.data array, and thus cannot select a groupHeader row that exists in the groupingHeaderCache. One of our requirements is to programmatically select a group row, which isn't possible unless hacked together using selectRowByVisibleIndex.

This issue is relatable to #6126 and #6145.