OSD + Notification isolation from island in settings

### Feature Description

Add a toggle in the island allowing you to seperate your osd from your island, alongside your notifications using the default layout instead of the hardcoded island one.

### Use Case

Fullscreen applications, you cant see it. The island is thin, you have to move your head. Having the better feedback of the noise or being able to see the notification in its full instead of having to click on notifications. OSD so you can see without bothering looking up for the island.

### Compositor(s)

All compositors

### If Other, please specify

_No response_

### Proposed Solution

Add a config flag that just disables using osd or notifications in the settings making it fall back to the default usable one. Isolation instead of usage making it simpler and just use the default old one instead of the new one with less feedback and such. Leverages current code and everything without having to remake stuff.

### Alternatives/Existing Solutions

_No response_