Bad check on poll_title causes <t></t> to render in poll question field when editing a post without a poll question

posting.php:1673 includes this check when deciding whether or not to run the message decoder on the poll title: !$bbcode_utils->is_empty($post_data['poll_title']). Checking whether the formatted poll title is empty and doing nothing if so means that “empty” poll titles get sent to templates as the encoded text <t></t>. Either there should be an else-condition that sets $post_data['poll_title'] to the empty string, or there is some earlier condition which is failing which is supposed to do that already (there are a lot of earlier isset-checks on the poll_title field).