A regressed issue should edit the Slack message to mark it as such

You can see [this issue](https://sentry.sentry.io/issues/4557158402) resolved by me via Slack: <img width="512" alt="image" src="https://github.com/getsentry/sentry/assets/44410/ced59ee9-c573-4cfc-b9b4-9c71e084b16e"> After I resolved it, another event came in and regressed it: <img width="617" alt="image" src="https://github.com/getsentry/sentry/assets/44410/f1d3da03-fce4-478f-8d79-2881cf601c52"> It shows as resolved in Slack. We should edit the Slack message and mark it as re-opened. Ideally, we should do a 2-way sync between Sentry and every integration. We can punt that to later.