change unapplied cateogry filter to empty instead of x (#858) (#860)

(cherry picked from commit d1f5d3b)

Signed-off-by: Derek Ho <dxho@amazon.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

public/components/integrations/components/available_integration_overview_page.tsx

@@ -163,7 +163,7 @@ export function AvailableIntegrationOverviewPage(props: AvailableIntegrationOver
           <div className="ouiFilterSelect__items">
             {items.map((item, index) => (
               <EuiFilterSelectItem
-                checked={item.checked ? 'on' : 'off'}
+                checked={item.checked ? 'on' : undefined}
                 key={index}
                 onClick={() => updateItem(index)}
               >