IBMa Accessibility Checker ARIA guidance incorrect for Carbon Search/TableToolbarSearch component

[dakahn]

Users of the Search/TableToolbarSearch components are rightfully encountering an Accessibility Checker error when they neglect to set the labeltext prop. Not setting the label text prop results in a label-less input.

The guidance in the Accessibility Checker instructs the user to add ARIA to the component to correct the problem, which usually would be a good solution for a search landmark. But we set the ARIA for them via the labelText prop and don't allow them to set it themselves directly so their ARIA applied directly gets thrown out.

This could be fixed via requiring the labelText prop on the aforementioned components, but there are cases where there is only one search on the page and a programmatic label isn't required.