fix(vite): change vite build hook to buildStart

[nader-eloshaiker]

The Vite Plugin generates the sitemap.xml after vite copies the contents of the public folder into the dist and so not part of the deployment.

The plugin should generate the sitemap.xml first before the bundle is generated so that it can be included in the dist folder.

To achieve this, the plugin has to change the Vite build hook from closeBundle to buildStart.