Support customizing tab width

[unional]

Is your feature request related to a problem? Please describe.

When the mdx file contains code block that uses tab to indent the code, storybook is rendering the tabs as 8 spaces wide.

Just like "tab" won the "tab vs space" debate due to accessibility concern,
the same applies here which would be great to make that configurable / changeable when storybook runs.

Describe the solution you'd like

Add an input in the setting to change the tab rendering to something else,
and provide a way in the config (main.ts or preview.tsx) to define the default tab width.

Describe alternatives you've considered

No response

Are you able to assist to bring the feature to reality?

yes, I can

Additional context

No response