[TESTS] Fix a couple of issues from last changes

plugins/ActivityPub/Util/Model/Note.php

@@ -188,7 +188,7 @@ class Note extends Model
 
         $attention_targets = [];
         foreach ($to as $target) {
-            if ($target === 'https://www.w3.org/ns/activitystreams#Public') {
+            if (\in_array($target, ActivityPub::PUBLIC_TO)) {
                 continue;
             }
             try {
@@ -217,7 +217,7 @@ class Note extends Model
         }
 
         foreach ($cc as $target) {
-            if ($target === 'https://www.w3.org/ns/activitystreams#Public') {
+            if (\in_array($target, ActivityPub::PUBLIC_TO)) {
                 continue;
             }
             try {