Export currentPerspective() from debugger window

Change-Id: Icef2b21e86f678bdd9f10dc26197db97bba6ade9
Reviewed-by: hjk <hjk@qt.io>

src/plugins/debugger/debuggerplugin.cpp

@@ -3610,6 +3610,11 @@ void selectPerspective(const QByteArray &perspectiveId)
     dd->m_mainWindow->restorePerspective(perspectiveId);
 }
 
+QByteArray currentPerspective()
+{
+    return dd->m_mainWindow->currentPerspective();
+}
+
 QWidget *mainWindow()
 {
     return dd->m_mainWindow;