Row groups of size 1 should have the option to be shown in non grouped format

## Use case

I have a set of rows where some rows have a group size of 1. I would like the option to show these rows in the non grouped format

## Proposed solution

I am not sure of an easy way of doing this but a couple options could be:
1. An attribute/property on the `DataGrid` component that tells the grid to not group rows that have a group size of 1.
2. Add some sort of flag to the `rowGrouper` return object that tells the grid to not group rows with group size of 1.