Steps to reproduce:

1. Log in to back office.
2. Go to Product catalog / Attribute groups.
3. Create a new Attribute group.
4. Select previously created Attribute group and delete it.
5. Verify if success deletion notification appears.

Actual result:

See attached screenshot.

Notification is not displayed.

Expected result:

Notification with message of success deletion appears.

e.g. taken from Attributes:   "Attribute definition 'ABC' removed." 

Edit:
Please bear in mind that when this fix will be merged Attribute Groups test suite will fail and there is needed to uncomment one step from Attribute group can be deleted scenario in file features/AttributeGroups.feature (product catalog bundle).