message: Fix webex adapter to support FormData
diff: @@ -317,14 +317,22 @@ export class WebexAdapter extends BotAdapter {
  // transform activity into the webex message format
  // https://developer.webex.com/docs/api/v1/messages/create-a-message
  - const message = {
  - roomId: activity.conversation ? activity.conversation.id : null,
  - toPersonId: activity.conversation ? null : activity.recipient.id,
  - toPersonEmail: activity.channelData && activity.channelData.toPersonEmail ? activity.channelData.toPersonEmail : null,
  - text: activity.text,
  - markdown: activity.channelData ? activity.channelData.markdown : null,
  - files: activity.channelData ? activity.channelData.files : null
  + const message: any = {
  + files: activity.channelData ? activity.channelData.files : ''
  };
  + if (activity.text) {
  + message.text = activity.text;
  + }
  + if (activity.channelData && activity.channelData.markdown) {
  + message.markdown = activity.channelData.markdown;
  + }
  + if (activity.conversation && activity.conversation.id) {
  + message.roomId = activity.conversation.id;
  + } else if (!activity.conversation && activity.recipient.id) {
  + message.toPersonId = activity.recipient.id;
  + } else if (activity.channelData && activity.channelData.toPersonEmail) {
  + message.toPersonEmail = activity.channelData.toPersonEmail;
  + }
  let response = await this._api.messages.create(message);
  