Merge pull request #8537 from matrix-org/rav/simplify_locally_reject_invite

changelog.d/8537.misc

synapse/events/builder.py

synapse/handlers/message.py

synapse/handlers/room.py

synapse/handlers/room_member.py

tests/handlers/test_message.py

tests/handlers/test_presence.py

tests/replication/test_federation_sender_shard.py

tests/storage/test_redaction.py