Proper formatting for Flow Run notifications sent to MSTeams

[hateyouinfinity]

First check

• [X] I added a descriptive title to this issue.
• [X] I used the GitHub search to find a similar request and didn't find it.
• [X] I searched the Prefect documentation for this feature.

Prefect Version

2.x

Describe the current behavior

Currently MSTeams notifications sent to notify of a flow run state change are not formatted properly. Example:

By default notification payload is generated via DEFAULT_MESSAGE_TEMPLATE which uses newlines. However, MSTeams notifications are parsed as Markdown (ref) => multiple newlines are collapsed into a single newline, while a single newline is ignored.

Describe the proposed behavior

Use a different template for MSTeams notifications.

How a notification would look with <br>s instead of newlines:

Example Use

No response

Additional context

No response

[bunchesofdonald]

Thanks for the issue report @hateyouinfinity !