activitypub: user view: remove totalInbox from user inbox view

It is not really feasible to quickly calculate the totalItems value and
it shouldn't be trusted anyway.

lib/pleroma/web/activity_pub/views/user_view.ex

@@ -224,7 +224,6 @@ def render("inbox.json", %{user: user, max_id: max_qid}) do
       "id" => "#{iri}?max_id=#{max_id}",
       "type" => "OrderedCollectionPage",
       "partOf" => iri,
-      "totalItems" => -1,
       "orderedItems" => collection,
       "next" => "#{iri}?max_id=#{min_id}"
     }
@@ -233,7 +232,6 @@ def render("inbox.json", %{user: user, max_id: max_qid}) do
       %{
         "id" => iri,
         "type" => "OrderedCollection",
-        "totalItems" => -1,
         "first" => page
       }
       |> Map.merge(Utils.make_json_ld_header())