Scalar Theme handling is not ideal

[marioparaschiv]

Custom CSS can be used to prevent Elysia from injecting its own theme.

elysia-openapi/src/scalar/index.ts

Line 152 in 070919e

${config.customCss ?? elysiaCSS}

Elysia injecting its own CSS is causing themes to be broken.

Scalar seems to already have a theme for Elysia, I believe it would be better to default to that rather than inject that CSS.

Also, customCss is missing from the Config interface