selectableRows messes up other Material UI elements

## Expected Behavior
Other Material UI elements shouldn't be affected by the datatable.

## Current Behavior
When I enable a single selectable row, it messes up the design of all the other material ui elements, like objects and the app bar.

## Steps to Reproduce (for bugs)

1. Enable selectable rows
2. Have other Material UI elements

## Your Environment

| Tech | Version |
|--------------|---------|
| Material-UI | ^5.6.3 |
| MUI-datatables | ^3.8.5 |
| React | ^17.0.2 |
| browser | chrome |
| etc | |

Start by reproducing the issue with MUI-datatables 3.8.5, React 17.0.2, and Material-UI 5.6.3 in Chrome. Enable a single selectable row alongside other Material UI elements, then identify what changes in the table or surrounding layout; done means selectable rows no longer affect the other elements.

Written by the indexing model from the issue text.