Refactor username mapping in activity context filter.

Replaced array_map with a foreach loop for clarity and maintainability when extracting usernames from work referrers. This ensures better readability and aligns with coding standards.

src/Bundle/ChillActivityBundle/Service/DocGenerator/ListActivitiesByAccompanyingPeriodContext.php

@@ -143,7 +143,10 @@ class ListActivitiesByAccompanyingPeriodContext implements
             array_filter(
                 $works,
                 function ($work) use ($user) {
-                    $workUsernames = array_map(static fn (User $user) => $user['username'], $work['referrers'] ?? []);
+                    $workUsernames = [];
+                    foreach ($work['referrers'] as $referrer) {
+                        $workUsernames[] = $referrer['username'];
+                    }
 
                     return \in_array($user->getUserIdentifier(), $workUsernames, true);
                 }