Fix upgrade error that was hit on 7.7.21 to 7.7.22. Fixes bug #11146

docs/changelog/7.x.x.txt

@@ -22,6 +22,7 @@
  - fixed #10888: Issues with adding points to Maps
  - fixed #10993: Editor drops last letter if s
  - fixed #11139: referencing an item in the clipboard
+ - fixed #11146: Upgrade Error 7.7.21 to 7.7.22 
 
 7.8.1
  - mark $session->datetime->time as deprecated and remove its use from core code

docs/upgrades/upgrade_7.8.1-7.8.2.pl

@@ -95,7 +95,8 @@ sub correctWikiAttachmentPermissions {
     PAGE: while (my $wikiPage = $pageIterator->()) {
         my $wiki = $wikiPage->getWiki;
         next PAGE unless $wiki && $wiki->get('allowAttachments') && $wikiPage->getChildCount;
-        foreach my $attachment (@{ $wikiPage->getLineage(['children'])}) {
+        ATTACHMENT: foreach my $attachment (@{ $wikiPage->getLineage(['children'], { returnObjects => 1, })}) {
+            next ATTACHMENT unless $attachment;
             $attachment->update({ groupIdEdit => $wiki->get('groupToEditPages') });
         }
     }