Bug when using in_memory_cache

Description

A nasty bug in local testing. The bug occurs when we do not use the in_memory_cache=False when creating connections:

ds_client, do_client = SyftboxManager.pair_with_in_memory_connection(
    sync_automatically=False, use_in_memory_cache=False
)

The error shows up as dataset changes not percolating from DO to DS.