docs(examples): fix StackBlitz example for module federation

[SamVerschueren]

This PR fixes the link when clicking on the StackBlitz button. It will install the dependencies, run the npm start command and open a second blank terminal.

I also removed the .stackblitzrc because it's covered by the query parameters and allows more flexibility like opening a second or third terminal and what not. So in this case, the .stackblitzrc is not needed.

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[chenxsan]

Can you update https://github.com/webpack/webpack.js.org/blob/master/src/content/plugins/module-federation-plugin.mdx as well?

[SamVerschueren]

Good catch!

[chenxsan]

Thanks for the contribution!