qt: Default destructors where applicable

Makes code consistent with our style of defaulting special member
functions where applicable.

src/yuzu/debugger/graphics/graphics_surface.cpp

@@ -34,7 +34,8 @@ static Tegra::Texture::TextureFormat ConvertToTextureFormat(
 
 SurfacePicture::SurfacePicture(QWidget* parent, GraphicsSurfaceWidget* surface_widget_)
     : QLabel(parent), surface_widget(surface_widget_) {}
-SurfacePicture::~SurfacePicture() {}
+
+SurfacePicture::~SurfacePicture() = default;
 
 void SurfacePicture::mousePressEvent(QMouseEvent* event) {
     // Only do something while the left mouse button is held down