title: Realm Collection notification not firing for updates not impacting query
body: <p>I have run into an issue in Realm Objective-C v2.4.3 where the collection notification block is not firing for a modification if the modification does not affect the overall query results.</p>
  <p>To give a simplified example.</p>
  <p>A <code>Feed</code> object and <code>FeedItem</code> object. Feed has an <code>items</code> RLMArray property.</p>
  <pre><code>RLMArray&lt;FeedItem *&gt;&lt;FeedItem&gt; *items
  </code></pre>
  <p>I have a collection notification block set up for RLMResults where the query is:</p>
  <pre><code>[Feed objectsWhere:@&quot;ANY items.status &gt; 0&quot;]
  </code></pre>
  <p>Insertion changes will fire if I modify the status property from 0 -&gt; 1. As would deletions if I had an upper bounds to the query and it moved out of that. However, any changes to a FeedItem's status property that continues to match the query (such as modifying it from 1 -&gt; 2) will not trigger the notification change block as the overall query results are not impacted by this change.</p>
  <p>I would've expected this change to fall under a modification as mentioned in the collection docs?</p>
  <blockquote>
  <ul>
  <li><p>You’re notified about modifications whenever a property of an object
  has changed, which was previously part of the collection and is still
  part of it.</p>
  </li>
  <li><p>You modify the age property of a Dog belonging to that Person.</p>
  </li>
  <li><p>This makes it possible to discretely control the animations and
  visual updates made to the content inside your UI, instead of
  arbitrarily reloading everything each time a notification occurs.</p>
  </li>
  </ul>
  </blockquote>
  <p>Am I missing something to get this functionality working? The CollectionView's datasource is the RLMResults and I would like to reload an individual CollectionViewCell to reflect the update to the FeedItem's status.</p>