Remove duplicate publish checks

[colinrotherham]

This PR removes the duplicate yarn lint && yarn test checks from the prepublishOnly script

They're already run via GitHub Action release.yml workflow steps

It fixes the issue publishing v6.0.0-beta.1 where JS-DevTools/npm-publish@v1 likely sets NODE_ENV=production which overrides the Babel @babel/preset-env modules transform as shown below:

nhsuk-react-components/babel.config.cjs

Lines 22 to 24 in 3b2974c

	// Apply ES module transforms for Jest
	// https://jestjs.io/docs/ecmascript-modules
	modules: NODE_ENV === 'test' ? 'auto' : false,

The lines above set modules: false to prevent ES modules being transformed by default

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[colinrotherham]

Thanks @edwardhorsford

We'll know fairly quickly if this worked or not, I'll tag v6.0.0-beta.1 again and see what happens