a11y: announce dialog text in package manager

extensions/packageManager/src/components/WorkingModal.tsx

@@ -3,8 +3,10 @@
 
 /** @jsx jsx */
 import { jsx } from '@emotion/core';
+import { useEffect } from 'react';
 import { Dialog, DialogType } from 'office-ui-fabric-react';
 import { LoadingSpinner } from '@bfc/ui-shared';
+import { useApplicationApi } from '@bfc/extension-client';
 
 import { modalControlGroup } from './styles';
 
@@ -13,6 +15,12 @@ export interface WorkingModalProps {
   title: string;
 }
 export const WorkingModal: React.FC<WorkingModalProps> = (props) => {
+  const { announce } = useApplicationApi();
+
+  useEffect(() => {
+    announce(props.title);
+  }, [props.title]);
+
   return (
     <Dialog
       dialogContentProps={{