[Controller][Security] Fullname is not setup automatically upon registering anymore.

[ENTITY][Actor] Changes to accomodate fullname from potentially being null.
[ENTITY][Note] Changes to accomodate fullname from potentially being null.

src/Entity/Note.php

@@ -241,7 +241,7 @@ class Note extends Entity
         return Actor::getNicknameById($this->actor_id);
     }
 
-    public function getActorFullname(): string
+    public function getActorFullname(): ?string
     {
         return Actor::getFullnameById($this->actor_id);
     }