Don't error on unverifie/unknownd devices.
When cross-signing is enabled, we no longer want to fail and
prompt the user to ack every device in the room. All the info should
be conveyed in the shield colour (although isn't fully just yet).
Fixes https://github.com/vector-im/riot-web/issues/11750
Requires https://github.com/matrix-org/matrix-js-sdk/pull/1150
