Add a type hints for service notices to the HomeServer object. (#9675)

changelog.d/9675.misc

synapse/handlers/sync.py

synapse/rest/client/v2_alpha/sync.py

synapse/server.py

synapse/server_notices/consent_server_notices.py

synapse/server_notices/resource_limits_server_notices.py

synapse/server_notices/server_notices_manager.py

synapse/server_notices/server_notices_sender.py

synapse/server_notices/worker_server_notices_sender.py

synapse/storage/databases/main/deviceinbox.py

synapse/storage/databases/main/monthly_active_users.py