renamed absence module

lib/view/pages/absence_report/absence_report_view.dart

@@ -158,7 +158,7 @@ class _AbsenceReportViewState extends State<AbsenceReportView> {
 
   @override
   Widget build(BuildContext context) => Scaffold(
-    appBar: AppBar(title: const Text('Krankmeldung')),
+    appBar: AppBar(title: const Text('Abwesenheitsmeldung')),
     body: _done ? const _SubmittedView() : _buildBody(context),
   );