`IconButton` with tooltip is incompatible with `ButtonGroup`

[iansan5653]

When IconButton renders tooltips, it inserts an additional element after the button. This in turn breaks ButtonGroup's use of the :last-child selector to set border-radii, causing an IconButton at the end of a ButtonGroup to have square corners:

[langermank]

Thanks! I think this is a duplicate and we have an open PR addressing this so going to close.

PR: #5123
Duplicate issue: #4129

[iansan5653]

Awesome, thanks!