fix(network): fix countMap prop

Author: DAreRodz

src/networks/network.js

@@ -4,7 +4,7 @@ import { get } from 'mobx';
 export default types
   .model('Network')
   .props({
-    countsMap: types.optional(types.map(types.maybe(types.number)), {}),
+    countsMap: types.optional(types.map(types.maybeNull(types.number)), {}),
   })
   .views(self => ({
     count({ type, id }) {