Allow screenreader users to easily access and use the AdvancedSearch UI.
[ x] Allow general keyboard interaction ( see T181162 )
[ ] Set collapse / expand states to the expandable pane
[ ] Set `role=button` on clickable elements ( expandable pane / pills )
[ ] Set fitting ARIA roles to interactive elements ( see  )
[ ] Think of a way to access help texts
- It seems the full description of the help text is now marked as the description of the textfield. That seems a bit over the top (too much description). The (i) widget is interactive, but is not connected to behaviour.. ---> Small investigation what is left over that should be done
 The file type dropdown cannot be navigated over the specific file types, just the categories (Audio/video etc) using VoiceOver are browsable.
 The file type dropdown does not allow you to descend (ctrl-option-space) into the list with VoiceOver
 "Search in" uses <strong>, already an indicator that this is not semantic. The label is not associated with the multi select widget beneath it.
 The per field description is currently read as. `File type:Description:Searches only for files of the selected type.`. We should try adding spaces between the elements (though it might be tidy is filtering these out right now) and avoid using : for stylistic purposes.
 The file size textfields for the size are not labelled and connected to the file height label and "greater than dropdown.---> Can Michi reproduce?
 The file size unit field only reflects its current value, but not its function.type dropdown does not allow you to descend (ctrl-option-space) into the list with VoiceOver ---> Can Michi reproduce?
 "Search in" should be a lable for the namespace selection input box. <strong> should be replaced by <label> or maybe even a label widget
 File width and File height labels are not connected to any fields. It should lead you to at least the first drop down (e.g. "greater than"). If possible, "px" can also be added as a label to the field