Make the room power levels optional as they can be missing depending on what state events are requested

ElementX/Sources/Services/Room/RoomPowerLevelProxyProtocol.swift

@@ -11,6 +11,8 @@ import MatrixRustSDK
 protocol RoomPowerLevelsProxyProtocol {
     var values: RoomPowerLevelsValues { get }
     
+    var userPowerLevels: [String: Int64] { get }
+    
     func canOwnUser(sendMessage messageType: MessageLikeEventType) -> Bool
     func canOwnUser(sendStateEvent event: StateEventType) -> Bool
     func canOwnUserInvite() -> Bool