Modifying Notify Properties no longer updates the NotifyName in Blueprints with custom GetNotifyName function.

If after placing a notify on an anim sequence timeline you modify a property that is used in the GetNotifyName function of a blueprint notify in engine version previous to 5.5 (5.4.3 for example) the notify name on on the timeline will be updated as soon as you finish changing the property.

In 5.5 however changing the property does not update the name and you have to do something else like moving the notify to get it to update the notify name on the timeline.

Steps to Reproduce

1. Create a blueprint AnimNotify.
2. Add a string variable and expose it to be instance editable.
3. Override the GetNotifyName function. Return your new string variable as the NotifyName.
4. Add this notify to the timeline of an anim sequence.
5. Notice that initially the notify name on the timeline will show up as None as that is the value in your string variable.
6. In the details panel set the string property's value to something else
7. Notice that the name in the timeline doesn't update.
8. Note that moving the notify on the timeline will cause it to refresh the name.