Group CORE

Dark mode Background

Name and description	Type	Value
`[collapsed]` Remove margin between items ( `2px` by default)	`boolean`
`[rounded]` The first and the last items are rounded	`boolean`
`[orientation]` Horizontal or vertical direction of group	`TuiOrientation`	`null`
`[size]` Size of rounding	`TuiSizeL`	`null`