Fix Narrator reading out attachments and timestamps in transcript

[corinagum]

Fixes #2193
Fixes #2150

Changelog Entry

• Fix #2193. Fix Adaptive Card/attachments do not get read by Narrator, by @corinagum in PR #2226
• Fix #2150. Fix timestamps read by Narrator, by @corinagum in PR #2226

Description

A previous change to Web Chat made screenreaders ignore attachments and the timestamp. attachments will no longer be ignored, and timestamps have been set to be read as mm/dd/ hh:mm by the narrator.

Specific Changes

• Minor sample link fix on root README
• To reduce linting errors, React Legacy Lifecycle methods have been updated with the UNSAFE_ prefix.
• <span> has been added in Web Chat to force screen reader to behave more uniformly across browsers. To prevent the screen reader reading the same thing twice, the corresponding displayed element has been marked with aria-disabled=true
• There is an Edge bug where Adaptive Cards read by Narrator does not read some texts. This is not a Web Chat issue, unfortunately
• NVDA does not read timestamps in the correct order. This is also a browser issue. :/

Please note that there have been additions made to our Localization strings, and native speakers of non-English languages are invited to perform PRs with these new additions. Thank you! :)

Testing json file:

{
  "$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
  "type": "AdaptiveCard",
  "version": "1.0",
  "body": [
    {
      "type": "Image",
      "url": "http://herbi.org/ImagesNew/Glass.jpg",
      "altText": "A stained-glass window of the Ninja Bot",
      "size": "stretch"
    },
    {
      "type": "TextBlock",
      "spacing": "medium",
      "size": "default",
      "weight": "bolder",
      "text": "Welcome to Bill the Ninja Bot 2019!",
      "wrap": true,
      "maxLines": 0
    },
    {
      "type": "TextBlock",
      "size": "default",
      "isSubtle": "yes",
      "text": "Ask me anything!",
      "wrap": true,
      "maxLines": 0
    }
  ],
  "actions": [
    {
      "type": "Action.OpenUrl",
      "title": "Learn about Azure Cognitive Services",
      "url": "https://azure.microsoft.com/en-us/services/cognitive-services/"
    }
  ]
}

---

• Testing Added

[coveralls]

Coverage increased (+0.06%) to 64.94% when pulling 18d2d01 on corinagum:fix-2193 into 18a9a3b on microsoft:master.

[compulim]

• In CarouselFilmStrip.js line 143, you will see <Timestamp ... />. Can you remove the aria-hidden prop there? It is because Timestamp.js no longer support aria-hidden prop.
• Also in CarouselFilmStrip.js line 132, you will see <Bubble fromUser...>, this one does not set the required aria-hidden prop.

Thanks for cleaning up unused props. 👍

[corinagum]

Okay, final fixes are in. I'll do one more sanity check before merging, probably by Monday. If anyone wants to comment or pull this branch to test before that merge, please feel free to do so. :)