[Bug]: Duplicate events shown in the UI

[jvstme]

Steps to reproduce

1. Create at least 21 events.
2. View them all on the Events page by scrolling down.

Actual behaviour

Every 20-event batch (except the top 20 events) is duplicated.

For example, this screenshot shows the start of a duplicated batch. You can see that instead of descending gradually, timestamps suddenly just to a point of time that was already shown above.

Additionally, every request to /api/events/list is duplicated with the same parameters as you are scrolling.

https://github.com/user-attachments/assets/e6a7c257-3a80-4171-8fe3-ebd14f226ee8

Expected behaviour

No events are duplicated.

dstack version

0.20.0

Server logs

Additional information

The same issue is present in event tables added on Run, Job, and Fleet pages in #3392.