[docs] Remove unecessary createStyles in TypeScript Tabs demo

[imballinst]

This PR changes files in Tabs demo that uses createStyles when the Hook API makeStyles is already used. When using TypeScript, makeStyles alone is enough -- createStyles is used only if the HOC API withStyles is used -- because there are some type incompatibilities with some styles e.g. flexboxes (flexDirection, flexGrow, etc.).

Some parts of the demo I left them as they were -- because I think HOC is more appropriate in these cases instead of Hooks, e.g.

https://github.com/mui-org/material-ui/blob/44c335c3b3f8669b16901c5f777bb5ba9e9241c0/docs/src/pages/components/tabs/CustomizedTabs.tsx#L16-L49

This is because withStyles generates classes prop directly -- and almost all Material UI components can consume classes prop from its parent. As they are more like "reusable sub-components", inlining withStyles with the components is better in my opinion.

• I have followed (at least) the PR section of the contributing guide.

[mui-pr-bot]

No bundle size changes comparing 44c335c...cfcd311

Generated by 🚫 dangerJS against cfcd311

[eps1lon]

@imballinst Much appreciated. Thanks.