feat(series): adapt reversed pagination check

Changes have been requested in Zola PR: getzola/zola#2653.
This requieres minor adaptation on properties used to reversed pagination.

templates/page.html

@@ -198,7 +198,7 @@ <h1 class="article-title">
  {%- if "series" in loaded_section.extra and loaded_section.extra.series -%}
  {%- set_global series_section = loaded_section -%}
  {%- set_global series_ordered_pages = loaded_section.pages -%}
- {%- if loaded_section.paginated and loaded_section.paginate_reversed -%}
+ {%- if loaded_section.paginated | default(value=0) > 0 and loaded_section.paginate_reversed -%}
  {%- set_global series_ordered_pages = loaded_section.pages | reverse -%}
  {%- endif -%}
  {%- break -%}