Duplicate notifications are sent when the same device is added multiple times to Media.

Steps to reproduce:

1. Enable push notifications and create Trigger action.
2. Add the same device multiple times to the user media.
3. Trigger an event that sends a notification.

Actual result:
The device receives multiple identical notifications. The number of notifications corresponds to the number of times the same device was added to the Media.

Expected result:
The device should receive only one notification, even if the same device is added to the Media multiple times.