feat(headlines-feed): reduce max filter name length

- Changed max filter name length from 25 to 15 characters
- This adjustment allows filter names to be displayed in a single line on
the user's dashboard

Author: fulleni

lib/headlines-feed/widgets/save_filter_dialog.dart

@@ -27,7 +27,7 @@ class _SaveFilterDialogState extends State<SaveFilterDialog> {
   final _formKey = GlobalKey<FormState>();
   late final TextEditingController _controller;
 
-  static const _maxNameLength = 25;
+  static const _maxNameLength = 15;
 
   @override
   void initState() {