Media plugin ignores custom theme

[hacknug]

Is your feature request related to a problem? Please describe.
Support for dark mode was recently introduced (thank you! 🙏) but sanity-plugin-media currently doesn't respect a custom studio theme.

Describe the solution you'd like
I would love to see this plugin use the theme colors the rest of the studio uses instead of the ones it is currently using.

Describe alternatives you've considered
Adding custom CSS but it's not a good solution since things could potentially break when updating studio dependencies.

Additional context
The Themer app could be used to create different themes and test everything is working as expected: https://themer.sanity.build/