Make "(do not) expose the arcs" work always

### Feature Description

Right now, disabling "expose the arcs" works, EXCEPT when 2 bars meet. Then, arcs are always exposed, except for notifications, for some reason. See attached screenshots. If "expose the arcs" is off, it should always be off.

### Use Case

It's about shell and settings coherence.

### Compositor(s)

All compositors

### If Other, please specify

_No response_

### Proposed Solution

_No response_

### Alternatives/Existing Solutions

_No response_

Reproduce the issue by disabling “expose the arcs” and arranging two bars to meet, then compare the result with notifications and the attached screenshots. Trace the setting’s handling for the two-bar case across the supported compositors; done means arcs remain hidden whenever the setting is off.

Written by the indexing model from the issue text.