Fix chat message for reopened issue
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When an issue is opened/closed we get a message from our slack integration, however, when we reopen a closed issue, it still says "<issue> opened by <user>"
Can we make it `reopened`?
Since this is an integration there are no screenshots I can offer that'd be meaningful. This is really easy to reproduce (the steps to be taken are close and reopen the issue) but one would need to add a slack integration for the project.
I also checked the code and found that open/reopen do not seem like different `action` and of course it is clear that it is definitely not a `state`. Will also be happy to raise an MR for this (with a bit of help in navigating and general guidance).
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