Conversation: Also create participations for remote users.

Needed to get the participating user list.

lib/pleroma/conversation.ex

@@ -51,7 +51,7 @@ def create_or_bump_for(activity) do
          ap_id when is_binary(ap_id) <- activity.data["object"]["context"] do
       {:ok, conversation} = create_for_ap_id(ap_id)
 
-      users = User.get_users_from_set(activity.recipients)
+      users = User.get_users_from_set(activity.recipients, false)
 
       participations =
         Enum.map(users, fn user ->

test/conversation_test.exs

@@ -31,7 +31,7 @@ test "public posts don't create conversations" do
 
   test "it creates or updates a conversation and participations for a given DM" do
     har = insert(:user)
-    jafnhar = insert(:user)
+    jafnhar = insert(:user, local: false)
     tridi = insert(:user)
 
     {:ok, activity} =