[Direct Line Speech] Throw 'map' of null and 'actions' of null error

[compulim]

Screenshots

Version

4.8.1

Describe the bug

Direct Line Speech is sending various fields as null instead of undefined. The coalesces logic in Web Chat use JavaScript default function parameters and it didn't catch null.

Steps to reproduce

1. Go to https://microsoft.github.io/BotFramework-WebChat/03.speech/a.direct-line-speech/
2. Type "Hi" to the bot

Expected behavior

The bot should response correctly.

Instead, it showed a white screen.

Additional context

This fix will be rolled out as 4.9.0 as soon as possible.

Web Socket message on the wire

X-RequestId: 033f2a62ae93478eafbef5de63c53a69
Path:response
Content-Type:application/json; charset=utf-8

{
  "conversationId": "602f43a0-f8f6-4546-8c1b-9bb52c0e9bea",
  "messagePayload": {
    "type": "message",
    "id": "773ab1b2-7dc0-484e-8638-786cb9789e0f",
    "timestamp": "2020-05-11T22:50:13.7549Z",
    "localTimestamp": null,
    "localTimezone": null,
    "callerId": null,
    "serviceUrl": "urn:botframework:websocket:directlinespeech",
    "channelId": "directlinespeech",
    "from": {
      "id": "webchat-mockbot-streaming",
      "name": "webchat-mockbot-streaming",
      "aadObjectId": null,
      "role": null
    },
    "conversation": {
      "isGroup": false,
      "conversationType": null,
      "tenantId": null,
      "id": "602f43a0-f8f6-4546-8c1b-9bb52c0e9bea",
      "name": null,
      "aadObjectId": null,
      "role": null
    },
    "recipient": {
      "id": "602f43a0-f8f6-4546-8c1b-9bb52c0e9bea|0000",
      "name": null,
      "aadObjectId": null,
      "role": null
    },
    "textFormat": null,
    "attachmentLayout": null,
    "membersAdded": null,
    "membersRemoved": null,
    "reactionsAdded": null,
    "reactionsRemoved": null,
    "topicName": null,
    "historyDisclosed": null,
    "locale": null,
    "text": "Unknown command: `Hi!`.\r\n\r\nType `help` to learn more.",
    "speak": "Unknown command: I don't know Hi!. You can say \"help\" to learn more.",
    "inputHint": null,
    "summary": null,
    "suggestedActions": null,
    "attachments": null,
    "entities": null,
    "channelData": null,
    "action": null,
    "replyToId": "d4ffd33b-4fb3-4b1a-aa21-5f3f9092329b",
    "label": null,
    "valueType": null,
    "value": null,
    "name": null,
    "relatesTo": null,
    "code": null,
    "expiration": null,
    "importance": null,
    "deliveryMode": null,
    "listenFor": null,
    "textHighlights": null,
    "semanticAction": null,
    "transcript": null
  },
  "messageDataStreamType": 1,
  "version": 0.3
}

[Bug]