PixelPaint: Update SelectedColorWidget::m_color consistently

Author: https://github.com/ColinMink 🔰
Commit: dc89ac1463
Pull-request: https://github.com/SerenityOS/serenity/pull/11878
Reviewed-by: https://github.com/mustafaquraish ✅

Userland/Applications/PixelPaint/PaletteWidget.cpp

@@ -84,6 +84,7 @@ public:
         pal.set_color(ColorRole::Background, color);
         set_palette(pal);
         update();
+        m_color = color;
     }
 
     Function<void(Color const&)> on_color_change;