Handle Lobsters comment parsing TypeErrors

Too lazy to debug this:

2023-08-29 12:56:35,111 - root - INFO - Updating lobsters story: yktkwr, index: 55
Traceback (most recent call last):
  File "src/gevent/greenlet.py", line 854, in gevent._gevent_cgreenlet.Greenlet.run
  File "/home/tanner/qotnews/apiserver/server.py", line 194, in feed_thread
    valid = feed.update_story(story)
  File "/home/tanner/qotnews/apiserver/feed.py", line 74, in update_story
    res = lobsters.story(story['ref'])
  File "/home/tanner/qotnews/apiserver/feeds/lobsters.py", line 103, in story
    s['comments'] = iter_comments(r['comments'])
  File "/home/tanner/qotnews/apiserver/feeds/lobsters.py", line 76, in iter_comments
    parent_stack = parent_stack[:indent-1]
TypeError: unsupported operand type(s) for -: 'NoneType' and 'int'
2023-08-29T12:56:35Z <Greenlet at 0x7f92ad840ae0: feed_thread> failed with TypeError

apiserver/feeds/lobsters.py

@@ -100,7 +100,13 @@ def story(ref):
     s['title'] = r.get('title', '')
     s['link'] = SITE_LINK(ref)
     s['url'] = r.get('url', '')
-    s['comments'] = iter_comments(r['comments'])
+
+    try:
+        s['comments'] = iter_comments(r['comments'])
+    except TypeError:
+        logging.exception('TypeError iterating lobsters comments, skipping article.')
+        return False
+
     s['num_comments'] = r['comment_count']
 
     if 'description' in r and r['description']: