Python: close all info bars after language server setup

Change-Id: I607f7cb5a31f3db0c7d7d77011860a1ea87eb8d2
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/python/pythonplugin.h

@@ -36,9 +36,11 @@ class PythonPlugin : public ExtensionSystem::IPlugin
     Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QtCreatorPlugin" FILE "Python.json")
 
 public:
-    PythonPlugin() = default;
+    PythonPlugin();
     ~PythonPlugin() final;
 
+    static PythonPlugin *instance();
+
 private:
     bool initialize(const QStringList &arguments, QString *errorMessage) final;
     void extensionsInitialized() final;