feat: Option to disable override theme type

[KiruPoruno]

Feature description

Currently nothing except the light, dark and auto built-in themes work, you can switch to them, but they will switch away after a restart, this is especially annoying with the Midnight theme, which works very well with many themes, it just gets disabled.

Ideally the override would also auto disable if manually changing the built-in theme, as not many people even realize there's a setting menu for the overall theme functionality.

Motivation

It is easy to implement, and it would also clear up confusion for some as to why many built-in themes are not working.

This is especially useful with MonetTheme. This used to function just fine before the override was added, but since then it's been broken/removed.

Acknowledgements

• I have checked all open and closed feature requests and this is not a duplicate
• I have chosen an appropriate title.
• All requested information has been provided properly.