async/await is_server_admin (#7363)

changelog.d/7363.misc

synapse/api/auth.py

synapse/federation/federation_client.py

synapse/groups/groups_server.py

synapse/handlers/_base.py

synapse/handlers/directory.py

synapse/handlers/federation.py

synapse/handlers/groups_local.py

synapse/handlers/message.py

synapse/handlers/profile.py

synapse/handlers/register.py

synapse/handlers/room.py

synapse/handlers/room_member.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/storage/data_stores/main/registration.py

tests/handlers/test_profile.py

tests/handlers/test_register.py