Fixup synapse.replication to pass mypy checks (#6667)

changelog.d/6667.misc

synapse/replication/http/_base.py

synapse/replication/slave/storage/_base.py

synapse/replication/slave/storage/presence.py

synapse/replication/tcp/client.py

synapse/replication/tcp/commands.py

synapse/replication/tcp/protocol.py

synapse/replication/tcp/resource.py

synapse/replication/tcp/streams/_base.py

synapse/replication/tcp/streams/events.py

synapse/replication/tcp/streams/federation.py

tox.ini