Remove unneeded a11y workaround.
Remove unneeded a11y workaround.

I'd previously added role="rowgroup" as part of the investigation for the a11y
issues I logged in bug 1668701.  This is not needed and in fact perpetuates
the breakage that bug 1668707 corrects.

bill-mccloskey/searchfox,bill-mccloskey/searchfox,bill-mccloskey/searchfox,bill-mccloskey/searchfox,bill-mccloskey/searchfox,bill-mccloskey/searchfox