Replace deprecated Rollup plugins

What does this MR do and why?

1. Replaces a few deprecated Rollup plugins:

• https://github.com/vuejs/rollup-plugin-vue => https://github.com/vitejs/vite-plugin-vue2
• https://www.npmjs.com/package/rollup-plugin-terser => https://github.com/rollup/plugins/tree/master/packages/terser

2. Removes unneeded plugins:

• https://github.com/rollup/plugins/tree/master/packages/inject (we were not specifying any properties to inject, so this wasn't doing anything)
• https://github.com/zindex-software/rollup-plugin-import-resolver (the Vue file specified here is not being used at all; we should probably be handling Vue as a global instead. I'll do that in a follow-up MR)

3. Removes unneeded commonJS requireReturnsDefault configuration option. We'd needed this to resolve an issue with an Algolia package.

Screenshots, screen recordings, or links to review app

n/a

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Configure a local GitLab Docs environment: https://gitlab.com/gitlab-org/gitlab-docs/-/blob/main/doc/setup.md.
2. Compile the site: make compile
3. Validate the rollup bundles JS files without errors

Merge request acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this merge request.