I do not think there is a shortcut for it by default, but this can easily be done.
Go to your menu: Studio One > Keyboard Shortcuts...
In the search bar, type in 'list' and it should show up. Select it
Now on the right, highlight the emtpy space where is says 'Enter key'
Now you can put in any key you wish, or a combination like CTRL+H by just holding CTRL+H
It will let you know if you do choose any that are already assigned right below.
When you are satisfied with your choice, you click the 'Assign' button.