Allow icons in blind header

[network-interface-controller]

Problem:
Due to a user request we provided an option to switch between a plain list of items (AgGrid) and a grouped view. The latter categorizes the items in the list based on the cell values of a column. However, while the AgGrid can contain columns that display only icons in the cells (e.g. a status indicator) the blind titles have to be strings at the moment. Consequently, the grouped view does not reflect the list content correctly (icons are replaced by associated text).

Requirement:
Enable the blind headers to be objects which may consist of icons and text.

[silviowolf]

Related to #358

[silviowolf]

UX Weekly 2022-02-16

• intetgrate the ability to also state an icon additionally to the text (same way as text button does)
• create design and specs for dev together with Blind enhancement: Add option to show menu button in the blind header #358

[silviowolf]

Planned with IX-46