added guardian login with views for their assigned childs

lib/api/marianumcloud/nextcloud_ocs.dart

@@ -1,7 +1,7 @@
 import 'dart:convert';
 
-import '../../model/account_data.dart';
 import '../../model/endpoint_data.dart';
+import '../../session/session_manager.dart';
 
 /// Shared headers and URI builder for Nextcloud OCS v2 endpoints. Used by
 /// TalkApi, AutocompleteApi, FileSharingApi.
@@ -16,7 +16,7 @@ class NextcloudOcs {
   static Map<String, String> headers() => {
     'Accept': 'application/json',
     'OCS-APIRequest': 'true',
-    'Authorization': AccountData().getBasicAuthHeader(),
+    'Authorization': SessionManager().requireNextcloud().basicAuthHeader,
   };
 
   static Uri uri(String pathSuffix, {Map<String, dynamic>? queryParameters}) {