feat(button): circular icon button to appear round at minimum

[lubber-de]

Description

Whenever a circular icon button was used to reduce the padding but use text instead of an icon, the button does not appear as a circle at least (that is taken care of for circular label)

By adding a min width to a circular button this gets fixed. I intentionally added the minwidth directly to circular button (instead of circular icon button) as it saves an extra selector and the default min-width is already reached (because of the larger paddding) when a non icon button is used.

Screenshot

Before

After

Testcase

Remove CSS to see issue https://jsfiddle.net/lubber/do4tujhx/18/