fix: add publish event in deleteNotificationsById and export snap types

[hmalik88]

Explanation

• What is the current state of things and why does it need to change? The deleteNotificationsById doesn't fire an event with the updated list of notifications and thus, the updateBadge function inside the extension is not fired.
• What is the solution your changes offer and how does it work? Publish an event after notifications are deleted
• Are there any changes whose purpose might not obvious to those unfamiliar with the domain? Adding export for snap types, not able to pull the type out directly otherwise.

@metamask/notification-services-controller

• FIX: The deleteNotificationsById function did not fire an event with the updated notifications list, this was added after the function runs through all the notifications it needs to delete.

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes