Mod to function bp_the_topic_latest_post_excerpt()

[burtadsit]

This is a fix that should have been in the ticket for 'large character counts in topic' don't display in bp. I have no idea where that went. Anyway this goes along with not getting the entire topic and all replies. bp_the_topic_latest_post_excerpt() does that. This fix changes the fn to get the last post directly from info in the topic details.

`
function bp_the_topic_latest_post_excerpt() {

global $forum_template;

$post = bp_forums_get_post( $forum_template->topic->topic_last_post_id );
echo apply_filters( 'bp_the_topic_latest_post_excerpt', $postpost_text? );

}
`

[apeatling]

(In [1269]) Fixes #628 props burtadsit.