refactor: Switch from maestro to flutter integration tests

lib/pages/chat/chat_input_row.dart

@@ -382,6 +382,7 @@ class ChatInputRow extends StatelessWidget {
                             ),
                           )
                         : IconButton(
+                            key: Key('send_button'),
                             tooltip: L10n.of(context).send,
                             onPressed: controller.send,
                             style: IconButton.styleFrom(

lib/pages/chat/input_bar.dart

@@ -385,6 +385,7 @@ class InputBar extends StatelessWidget {
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
     return Autocomplete<Map<String, String?>>(
+      key: Key('chat_input_field'),
       focusNode: focusNode,
       textEditingController: controller,
       optionsBuilder: getSuggestions,