[ticket/11717] Use topic_posts_approved instead of topic_replies

Due to the move to soft-delete, the topic_replies column no longer exists
in the topics table. Instead, the column topic_posts_approved should be used.

PHPBB3-11717
[ticket/11717] Add 'has' to boolean variable and reduce line length

PHPBB3-11717
Merge pull request #1589 from marc1706/ticket/11717

[ticket/11717] Use topic_posts_approved instead of topic_replies