Improve discord messages

What does this MR do?

This is a community contribution from @sbingner, see !26978 (closed).

I'm opening this merge request because we were getting a Pipeline job activity limit exceeded! CI error and I've also added one spec.

Please review the changes alongside the previous discussions in !26978 (closed), but we will continue the conversation here.

@sbingner deserves all the credit, thanks ❤