Added users does not get a DM at the close of the ticket

[Sayrix]

Is your feature request related to a problem? Please describe.
When users gets added to a ticket via the /add command and that the ticket gets closed, only the opener gets a DM that the ticket has been closed.

Describe the solution you'd like
Users added via the /add command should also receive a DM saying something like "A ticket you have been added to has been closed"

Describe alternatives you've considered
.

Additional context
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