fix filter radio buttons (remove deprecated code)

frontend/lib/pages/list.dart

@@ -296,10 +296,7 @@ class ListPage extends StatelessWidget {
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
-              ListTile(
+              RadioGroup<int>(
-                title: const Text(Strings.author),
-                leading: Radio<int>(
-                  value: 0,
                 groupValue: provider.filterBy,
                 onChanged: (value) {
                   if (value != null) {
@@ -307,25 +304,19 @@ class ListPage extends StatelessWidget {
                     Navigator.pop(context);
                   }
                 },
-                ),
+                child: Column(
+                  children: [
+                    ListTile(
+                      title: const Text(Strings.author),
+                      leading: Radio<int>(value: 0),
                       onTap: () {
                         provider.setFilterBy(0);
                         Navigator.pop(context);
                       },
                     ),
-
                     ListTile(
                       title: const Text(Strings.quote),
-                leading: Radio<int>(
+                      leading: Radio<int>(value: 1),
-                  value: 1,
-                  groupValue: provider.filterBy,
-                  onChanged: (value) {
-                    if (value != null) {
-                      provider.setFilterBy(value);
-                      Navigator.pop(context);
-                    }
-                  },
-                ),
                       onTap: () {
                         provider.setFilterBy(1);
                         Navigator.pop(context);
@@ -333,6 +324,9 @@ class ListPage extends StatelessWidget {
                     ),
                   ],
                 ),
+              ),
+            ],
+          )
         );
       },
     );