Themes: Update Button and Button Group focus styles

[simeonoff]

• Button Group: Active state should be without the focus border (This behaviour is applied only in Fluent and Indigo and should be logged as a separate feature/issue for Material & Bootstrap). This is applicable for the Button component as well.
• Button: When we have an Outlined button and a Contained button, if the content is the same, both button widths should be the same, but now the border in the Outlined buttons adds four additional pixels to the button width. (this behaviour is in all themes, not only Indigo)

Originally posted by @AnjiManova in https://github.com/IgniteUI/igniteui-webcomponents/issues/1090#issuecomment-2006205959