Fix login with 9.83-10.10

This only adds protocol compatibility, the features aren't actually
implemented yet

src/client/thingtype.h

@@ -81,6 +81,7 @@ enum ThingAttr : uint8 {
     ThingAttrOpacity          = 100,
     ThingAttrNotPreWalkable   = 101,
 
+    ThingAttrNoMoveAnimation  = 253, // real value is 16, but we need to do this for backwards compatibility
     ThingAttrChargeable       = 254, // deprecated
     ThingLastAttr             = 255
 };