fix: do not load databack if there isn't a list

birb/core/datas.lua

@@ -36,10 +36,12 @@ end
 
 function DataManager:loadDatas()
     self.datapacks = {}
+    if (index.datapacks ~= nil) then
         for key, datas in pairs(index.datapacks) do
             self.core.debug:debug("datamanager", "loading data for " .. key)
             self.datapacks[key] = DataPack(datas[1], datas[2], datas[3], datas[4], datas[5])
         end
+    end
 end
 
 function DataManager:get(datapack, name)