Removing 'getTheme' from BasicList examples

[mltejera]

The basic list examples all use getTheme which does not respond to contextual theme changes, the modern v8 method for theming.

This PR updates them to use the useTheme hook. There's some rearrangement required since the styles are passed into the render functions. Sorry for the load PR.

More generally:

• Move render and style generating function to within the scope of the component.
• Apply useCallback for the renders, useMemo for the style generators.
• Tidy up some styles.

Addresses #30358

[fabricteam]

📊 Bundle size report

_{🤖 This report was generated against 6dbbed43b5a12846cbb4f781f8de8b62f010ebc9}

[codesandbox-ci]

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