Dismiss mention notification when `x` icon is clicked (#3782)

We were emitting the wrong kind of event, which caused the workspace to
never remove the notification.

Release Notes:

- N/A
15bf131065Antonio Scandurra committed on 12/22/2023, 2:23:53 PM· committed by GitHubparentsbb931442f3b408
1 file changedLine totals unavailable