Acknowledge notifications should not be visible in popup

Steps to reproduce:

1. Create admin user (add email media type)
2. Set RW permissions on host group
3. Add Action for this user, add acknowledge operations with option "Notify all involved"
4. Make trigger in PROBLEM state
5. As super admin acknowledge event
6. Open event popup on Problem page

Result: In popup two notifications, from "Problem" and from "Acknowledge". If open Event details in "Message actions" block only one message from "Problem"
Expected: Acknowledge notifications not visible in popup