[1554] Inject plugin in $root state & context

I was try to write and inject horizon.io plugin in the $root (app) with documented way:

export default ({ app, store }) => {
  app.$horizon = horizon
}

but something was wrong and the injected props will append into $store key:

As you can see, $horizon will added into $store -> $store.$horizon, and into $store.app -> $store.app.$horizon.

If I test like firebase example, the result will be the same: