pagination.ex: Drop atom keys in params

Atom keys could also have been transformed to string, or the other
way around but this one is more efficient and what we actually
expect with the current param_types in Pagination

lib/pleroma/pagination.ex

@@ -36,6 +36,12 @@ defp cast_params(params) do
       limit: :integer
     }
 
+    params =
+      Enum.reduce(params, %{}, fn
+        {key, _value}, acc when is_atom(key) -> Map.drop(acc, [key])
+        {key, value}, acc -> Map.put(acc, key, value)
+      end)
+
     changeset = cast({%{}, param_types}, params, Map.keys(param_types))
     changeset.changes
   end