cabana: display a clear button in filter string edit box (#26152)

display clear button
old-commit-hash: 1211ffbcf2

tools/cabana/messageswidget.cc

@@ -42,6 +42,7 @@ MessagesWidget::MessagesWidget(QWidget *parent) : QWidget(parent) {
 
   // message filter
   QLineEdit *filter = new QLineEdit(this);
+  filter->setClearButtonEnabled(true);
   filter->setPlaceholderText(tr("filter messages"));
   main_layout->addWidget(filter);