fix(php): Prevent a duplicate users_oidc (#892)

This commit prevent a duplicate users when we search them with the `apps/workspace/api/autoComplete/:term/:spaceId` api/rest.

lib/Service/WorkspaceService.php

@@ -65,6 +65,8 @@ private function searchUsersByDisplayName(string $term): array {
 		$term = $term === '*' ? '' : $term;
 		$users = $this->userManager->searchDisplayName($term, 50);
 
+		$users = array_unique($users, SORT_REGULAR);
+
 		return $users;
 	}