UI: Inline OBSBasic::ThemeChanged()

The majority of this method got removed in a prior commit [1]. Let's
inline the rest.

[1] 8dcfae9

Author: gxalpha

UI/window-basic-main.cpp

@@ -536,7 +536,10 @@ OBSBasic::OBSBasic(QWidget *parent)
 	connect(ui->broadcastButton, &QPushButton::clicked, this,
 		&OBSBasic::BroadcastButtonClicked);
 
-	connect(App(), &OBSApp::StyleChanged, this, &OBSBasic::ThemeChanged);
+	connect(App(), &OBSApp::StyleChanged, this, [this]() {
+		if (api)
+			api->on_event(OBS_FRONTEND_EVENT_THEME_CHANGED);
+	});
 
 	QActionGroup *actionGroup = new QActionGroup(this);
 	actionGroup->addAction(ui->actionSceneListMode);
@@ -11142,9 +11145,3 @@ float OBSBasic::GetDevicePixelRatio()
 {
 	return dpi;
 }
-
-void OBSBasic::ThemeChanged()
-{
-	if (api)
-		api->on_event(OBS_FRONTEND_EVENT_THEME_CHANGED);
-}

UI/window-basic-main.hpp

@@ -848,7 +848,6 @@ private slots:
 	void TBarReleased();
 
 	void LockVolumeControl(bool lock);
-	void ThemeChanged();
 
 	void UpdateVirtualCamConfig(const VCamConfig &config);
 	void RestartVirtualCam(const VCamConfig &config);