fix: return error on sanity level limit

Sometimes even SFW artworks will return sanity level limited error,
e.g. 110355001
this is likely a bug on Pixiv side,
we should not save the returned error image.

nazurin/sites/pixiv/api.py

@@ -32,6 +32,8 @@
 )
 from .models import PixivIllust, PixivImage
 
+SANITY_LEVEL_LIMITED = "https://s.pximg.net/common/images/limit_sanity_level_360.png"
+
 
 class Pixiv:
     api = AppPixivAPI()
@@ -261,6 +263,13 @@ def get_images(self, illust) -> List[PixivImage]:
                 width = height = 0
         else:
             url = illust.meta_single_page.original_image_url
+            if url == SANITY_LEVEL_LIMITED:
+                logger.warning(
+                    "Artwork {} is not available due to sanity level limit: {}",
+                    illust.id,
+                    illust,
+                )
+                raise NazurinError("Artwork not available due to sanity level limit.")
             destination, filename = self.get_storage_dest(url, illust)
             imgs.append(
                 PixivImage(