fix author display

shared/templates/styleguide2/includes/atoms/articles/header_author.html

-<div class="text-grey-185 mb-4 italic">
-  Autor: <span rel="author">
-    {% if page.author_page %}
-      <a
-        href="{{ page.author_page.url }}"
-        class="underline text-grey-100"
-      >{{ page.author_page.get_full_name }}</a>
-    {% else %}
-      {{ page.author }}
-    {% endif %}
-  </span>
-</div>
+{% if page.author_page or page.author %}
+  <div class="text-grey-185 mb-4 italic">
+    Autor: <span rel="author">
+      {% if page.author_page %}
+        <a
+          href="{{ page.author_page.url }}"
+          class="underline text-grey-100"
+        >{{ page.author_page.get_full_name }}</a>
+      {% elif page.author %}
+        {{ page.author }}
+      {% endif %}
+    </span>
+  </div>
+{% endif %}
\ No newline at end of file