Description of the new feature/enhancement

There is a site https://windowsterminalthemes.dev/, it shares many awesome color themes. I choose some of them, pasted in settings.schemes, then I may change the colorScheme daily depends on my feeling.

The Oh-My-Zsh has a similar feature, the random theme, a theme will be chosen randomly every time a new shell is opened.

Wish Windows Terminal could have something like that.

Proposed technical implementation details (optional)

Introduce a keyword like random, if the colorScheme field is set to random, then every time a new tag or window is opened, randomly choose a color schema from settings.schemes .