Add system option for theme controller

[RTSAjwad]

The current theme controller supports manually picking themes. The default behavior without a theme controller is simply using the system setting. The theme controller could allow for choosing system as an option. That way you can have a theme controller on the page whilst still keeping default functionality if wanted. A drop down theme controller could have:

• System
• Light
• Dark

[saadeghi]

https://daisyui.com/components/theme-controller/#theme-controller-using-a-dropdown

"Default" is system

[RTSAjwad]

Thank you for the swift reply! I realized myself after posting that mine wasn't behaving as I intended due to the theme being set manually on the tag. Apologies for wasting your time.