CoPilot: Fix leak in authwidget

Also fixes a crash when the state check returns after the widget
was already deleted.

Change-Id: I04256e6ba686469f18ebdb75c73e12cecf330bed
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/copilot/authwidget.cpp

@@ -48,6 +48,12 @@ AuthWidget::AuthWidget(QWidget *parent)
     });
 }
 
+AuthWidget::~AuthWidget()
+{
+    if (m_client)
+        LanguageClientManager::shutdownClient(m_client);
+}
+
 void AuthWidget::setState(const QString &buttonText, bool working)
 {
     m_button->setText(buttonText);

src/plugins/copilot/authwidget.h

@@ -25,6 +25,8 @@ class AuthWidget : public QWidget
 
 public:
     explicit AuthWidget(QWidget *parent = nullptr);
+    ~AuthWidget() override;
+
     void updateClient(const Utils::FilePath &nodeJs, const Utils::FilePath &agent);
 
 private: