SHS-5571: A11y Level A: Empty headings on Vertical Timeline components (

#1502)

* fix(shs-5571): A11y Level A: Empty headings on Vertical Timeline components

* fix(shs-5571): minor code consistency fix in timeline template

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Co-authored-by: Mari Núñez <mariannuar@admins-MacBook-Pro.local>
Co-authored-by: Andrés Díaz Soto <andres.diaz.soto@gmail.com>

docroot/modules/humsci/hs_layouts/patterns/timeline/timeline.html.twig

@@ -9,7 +9,7 @@
 {% endif %}
 
 {% set timeline_content = timeline %}
-{% if timeline['field_hs_time_title'] is defined %}
+{% if timeline['field_hs_time_title'] is defined and timeline['field_hs_time_title'][0] is defined %}
   {% set timeline_content %}
     <{{ heading_tag }} class="hb-timeline__title">
       {{ timeline['field_hs_time_title'] }}