Fix #3395: fix pixiv API exception when uploading bad pixiv id images.

Fixes an exception when attempting to upload a Pixiv image from a
deleted work. The download strategy tries to fetch the source data in
the course of rewriting the URL, which fails if the work has been
deleted from Pixiv.

Raise a BadIDError and leave the URL as-is (don't rewrite it).

app/logical/downloads/rewrite_strategies/pixiv.rb

@@ -27,6 +27,8 @@ module Downloads
           data[:ugoira_content_type] = source.ugoira_content_type
         end
 
+        return [url, headers, data]
+      rescue PixivApiClient::BadIDError
         return [url, headers, data]
       end