[ci-en] gallery-dl not downloading all images when authenticated

[nomakewan]

I've noticed that if I use --cookies-from-browser firefox (I am logged into ci-en on Firefox) and try to download all galleries from a creator that I follow and support at their 0 yen tier (using it for testing purposes), the images from any particular gallery that are unique to the 0 yen tier do not download.

Example URL: https://ci-en.dlsite.com/creator/1429/article/1202958

Expected Behavior: When logged in and supporting at the 一般フォロワープラン0円（無料） tier, the attached image should download.

Actual Behavior: gallery-dl skips this gallery as if it has no images.

[mikf]

Found the bug: I thought it would be OK to search through just the much smaller articleBody instead of the entire HTML page:

diff --git a/gallery_dl/extractor/cien.py b/gallery_dl/extractor/cien.py
index bae86d07..378365eb 100644
--- a/gallery_dl/extractor/cien.py
+++ b/gallery_dl/extractor/cien.py
@@ -59,7 +59,7 @@ class CienArticleExtractor(CienExtractor):
         post = util.json_loads(text.extr(
             page, '<script type="application/ld+json">', '</script>'))[0]
 
-        files = self._extract_files(post.get("articleBody") or page)
+        files = self._extract_files(page)
 
         post["post_url"] = url
         post["post_id"] = text.parse_int(self.groups[1])