[PRM-155] WCAG 4.1.3 status messages: ARF download starts/completes without announcing (#650)

* Add download has started span to arf download

* Remove incorrect labelling

* Remove incorrect labelling

* adds assertive aria

* Adds assertive aria to finished download state

* adds download state announcer div

* Shows download status

* Adds class to aria div

* Makes download status announce on update

* Removes visually hidden for testing purposes

* Sets reader to assertive

* move aria div

* Hides aria div

* move Aria div to top of screen

* Changed aria announcement to polite

Author: jack-nhs

app/src/components/blocks/_arf/documentSearchResultsOptions/DocumentSearchResultsOptions.tsx

@@ -31,6 +31,22 @@ const DocumentSearchResultsOptions = (props: Props) => {
         filename: '',
     });
     const linkRef = useRef<HTMLAnchorElement | null>(null);
+    const [statusMessage, setStatusMessage] = useState('');
+    useEffect(() => {
+        switch (props.downloadState) {
+            case SUBMISSION_STATE.PENDING:
+                setStatusMessage('Download in progress.');
+                break;
+            case SUBMISSION_STATE.SUCCEEDED:
+                setStatusMessage('Download complete.');
+                break;
+            case SUBMISSION_STATE.FAILED:
+                setStatusMessage('Download failed.');
+                break;
+            default:
+                setStatusMessage('');
+        }
+    }, [props.downloadState]);
 
     useEffect(() => {
         if (linkRef.current && linkAttributes.url) {
@@ -70,6 +86,14 @@ const DocumentSearchResultsOptions = (props: Props) => {
 
     return (
         <>
+            <div
+                id="download-status"
+                aria-live="polite"
+                role="status"
+                className="nhsuk-u-visually-hidden"
+            >
+                {statusMessage}
+            </div>
             <div className="search-result-spinner-div">
                 {props.downloadState === SUBMISSION_STATE.PENDING ? (
                     <SpinnerButton