Investigate Canton party allocation timeouts

We started seeing logs like this on 3.4 reasonably frequently. I think so far only for the splitwell sync but that could potentially be because we just don't use that codepath on the global sync.

```
Waiting for allocation of dummyc517a29c::122053499dd4... on synchronizer splitwell::1220d5dfc1c0...::34-0 timed out
```