GHSA-VHR5-G3PM-49FM matrix-js-sdk will freeze when a user sets a room with itself as a its predecessor

Impact A malicious homeserver can craft a room or room structure such that the predecessors form a cycle. The matrix-js-sdk's getRoomUpgradeHistory function will infinitely recurse in this case, causing the code to hang. This method is public but also called by the 'leaveRoomChain' method, so...