[slack] Card with only ImageUrl shows empty text string

[mkevenaar]

When you create a new Card with only an ImageUrl ``` is shown twice in the response.

Expected Behavior

When only an ImageUrl is added, only the image is shown

Current Behavior

It also adds an empty line

Possible Solution

Steps to Reproduce (for bugs)

1. Create a card with New-PoshBotCardResponse -ImageUrl https://my.image.url/image.png
2. Display the card in Slack
3. Notice the empty backticks on top

Context

{"DataTime":"2019-08-23 09:00:48Z","Class":"SlackBackend","Method":"SendMessage","Severity":"Normal","LogLevel":"Debug","Message":"Sending card response back to Slack channel [REMOVED]","Data":{"color":"#008000","image_url":"https://my.image.url/image.png","fallback":"no data","text":"```\r\n```","mrkdwn_in":["text"]}}

The text element contains a new line: "text":"```\r\n```"

Your Environment

• Module version used: PoshBot v0.11.7
• Operating System and PowerShell version: PSVersion 5.1.14409.1018 running on WS12R2

[devblackops]

Thanks @mkevenaar. We'll get this fixed.

[mkevenaar]

@devblackops Thanks this worked perfectly!