More actionable notification message in case of www cert exchange failed

Summary: Improved message a bit to make it clear that VPN/Lighthouse is required on both sides - computer and mobile device. Also it will now show login link in case user is not signed in yet, because login is also required for www cert exchange.

Reviewed By: passy

Differential Revision: D28899558

fbshipit-source-id: 89de776f602a9f27a2c068efd8e3f08c28ec5f57

desktop/app/src/reducers/notifications.tsx

@@ -10,6 +10,7 @@
 import {Notification} from 'flipper-plugin';
 import {Actions} from './';
 import {getStringFromErrorLike} from '../utils';
+import React from 'react';
 
 export type PluginNotification = {
   notification: Notification;
@@ -200,7 +201,7 @@ export function removeNotification(
 
 export function addErrorNotification(
   title: string,
-  message: string,
+  message: string | React.ReactNode,
   error?: any,
 ): Action {
   // TODO: use this method for https://github.com/facebook/flipper/pull/1478/files as well
@@ -211,7 +212,14 @@ export function addErrorNotification(
     notification: {
       id: title,
       title,
-      message: error ? message + ' ' + getStringFromErrorLike(error) : message,
+      message: error ? (
+        <>
+          <p>{message}</p>
+          <p>{getStringFromErrorLike(error)}</p>
+        </>
+      ) : (
+        message
+      ),
       severity: 'error',
     },
   });