Update Stream-Connector to use ap_follower (#1787)

Co-authored-by: Automattic Bot <[email protected]>

Author: pfefferle

.github/changelog/1787-from-description

@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Update the Stream Connector integration to align with the new database schema.

integration/load.php

@@ -161,6 +161,8 @@ function register_stream_connector( $classes ) {
 add_filter(
 	'wp_stream_posts_exclude_post_types',
 	function ( $post_types ) {
+		$post_types[] = 'ap_actor';
+		// @todo remove in one of the next versions
 		$post_types[] = 'ap_follower';
 		$post_types[] = 'ap_extrafield';
 		$post_types[] = 'ap_extrafield_blog';