Check if the user has indeed not been federated with

Just updating the user triggered post fetching too, now it
shouldn't. It only happened in the AP user fetching since that's
what's used to update users

lib/pleroma/user.ex

@@ -1159,9 +1159,12 @@ defmodule Pleroma.User do
     if !is_nil(user) and !User.needs_update?(user) do
       user
     else
+      # Whether to fetch initial posts for the user (if it's a new user & the fetching is enabled)
+      should_fetch_initial = is_nil(user) and Pleroma.Config.get([:fetch_initial_posts, :enabled])
+
       user = fetch_by_ap_id(ap_id)
 
-      if Pleroma.Config.get([:fetch_initial_posts, :enabled]) do
+      if should_fetch_initial do
         with %User{} = user do
           {:ok, _} = Task.start(__MODULE__, :fetch_initial_posts, [user])
         end