[Bug][MultiColumnComboBox] Grouping text overlaps the item text

[WissamProgress]

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• Bug report

Current behavior

The grouping text overlaps overlaps the item text. This is reproducible is any grouping demo for the MultiColumnComboBox:

• https://www.telerik.com/kendo-react-ui/components/dropdowns/multicolumncombobox/grouping/#toc-basic-usage

Expected behavior

The group text is rendered correctly like in the DropDownList:

• https://www.telerik.com/kendo-react-ui/components/dropdowns/dropdownlist/grouping/#toc-basic-usage

Minimal reproduction of the problem with instructions

Add grouping to the MultiColumnComboBox component using the groupField and groupMode properties.

Reported in documentation feedback