Regression in accessibility with the Orca screen reader

[destructatron]

Please read through the README and the Man pages before submitting
Please also make sure that there isn't any prior issue describing this bug

Describe the bug
The Orca screen reader is seeing groups of notifications as a single list element, and thus will speak the entirity of the group, whereas before Orca would see the notifications as individual regardless of whether it came from the same app and tabbing through would make orca speak just that notification. Now only arrow keys work and Orca speaks the whole group, which isn't ideal when a new notification comes in, as focus changes and I'd have to start reading the group all over again.

To Reproduce
Steps to reproduce the behavior:

1. Start orca, if it started up successfully you should hear a text to speech voice say screen reader on.
2. Leave an application open like Discord which sends a decent amount of notifications.
3. When 2 or more notifications from the same app have been sent, press the bind to open the notifications list. Orca will speak the entire group, rather than treating each notification as individual.

Expected behavior
Orca should treat each notification as a separate object, allowing you to use arrow keys or tab and shift tab to move through them individually, and only the individual notification should be read.

Please provide logs if you're experiencing notification errors / bugs
Attach Gists for swaync logs by running G_MESSAGES_DEBUG=all swaync and (if applicable) application logs.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [Nix OS 24.05 unstable]
• Version [0.10.1]

Additional context
Orca has a built in notification centre, but notifications sent by swaync don't get picked up because the GTK widget when the notification appears isn't firing the accessible event needed for Orca to see it. If Orca was made aware of the notification in the first place, Orca could handle it. The only problem is that on Orca restarts the notification list is cleared, but that's no worse than how KDE is doing things. Their notification centre isn't accessible, but their notification daemon fires the accessible events and that's fine for most people.