Fix bug in uncollapsing behavior for new comments

Uncollapsing the new comments' parents wasn't working correctly if there
were several new replies in a chain. Because it's working from the
"leaf" comments back up towards the root, doing a continue when a
comment's state had already been set would cause uncollapsing parents to
fail - the deepest comment would uncollapse its parent, then its parent
would get skipped. If the parent was also new, this would mean that
*its* parent didn't get uncollapsed, even though it should have been.

tildes/tildes/models/comment/comment_tree.py

@@ -192,16 +192,13 @@ class CommentTree:
             if comment.is_deleted or comment.is_removed:
                 continue
 
-            # don't override any other collapsing decisions
-            if comment.collapsed_state:
-                continue
-
             # don't apply to the viewer's own comments
             if comment.user == self.viewer:
                 continue
 
-            # uncollapse the comment
-            comment.collapsed_state = "uncollapsed"
+            # uncollapse the comment (as long as it hasn't already had its state set)
+            if not comment.collapsed_state:
+                comment.collapsed_state = "uncollapsed"
 
             # fetch its direct parent and uncollapse it as well
             if comment.parent_comment_id: