bug: only a single resource is actively synced

[embik]

Describe the bug

In api-syncagent 0.4.0, we introduced a regression that stops syncing objects for PublishedResources except for a single, randomly chosen PublishedResource's object. As such, publishing more than one resource from a single api-syncagent is broken.

Steps To Reproduce

1. Create two PublishedResources.
2. Create objects for both resources on the kcp side.
3. Observe only one of the objects is synced.

Expected Behaviour

Multiple resources should be synced without problem.

Additional Context

No response