[Search][a11y] Fix table row screen reader error (elastic#203136)

##  Closes elastic#199113

Allows errors in the table row to be read by screen readers.

x-pack/plugins/enterprise_search/public/applications/shared/tables/reorderable_table/body_row.tsx

@@ -66,7 +66,14 @@ export const BodyRow = <Item extends object>({
         <EuiFlexGroup direction="column">
           {errors.map((errorMessage, errorMessageIndex) => (
             <EuiFlexItem key={errorMessageIndex}>
-              <EuiCallOut iconType="warning" size="s" color="danger" title={errorMessage} />
+              <EuiCallOut
+                role="alert"
+                aria-live="polite"
+                iconType="warning"
+                size="s"
+                color="danger"
+                title={errorMessage}
+              />
             </EuiFlexItem>
           ))}
         </EuiFlexGroup>