KnownState is not fully propagated between servers, when multiple servers are cross-connected #2874
Description
Tracking the toldKnownState through a Set is good enough for client/server communication or server to server communication, but shows some issues when multiple server nodes are connected to each other.
In the requestToJoin test we had 4 accounts connected to each other via server peers.
We've got a failure there when turning off the eager push of the dependencies to server peers in sendNewContent.
The waitForAllCoValueSync check here started to being stuck because the sync of this group is never confirmed by admin2 to admin1.