Fix webpack build in Vue 3

What does this MR do and why?

This change fixes the Webpack build to use Vue 3.

This changes addresses configuration issues that prevented webpack from building correctly when Vue 3 is enabled.

Why?

This enables users to locally run their GDK (with webpack for now) using Vue 3 to address possible issues.

References

• #554202 (closed)
• Previous attempt !150006 (closed)

Screenshots or screen recordings

Running Vue 2	Running Vue 3

How to set up and validate locally

This configuration fixes webpack:

1. Clean your cache (just in case) with yarn clean
2. Disable vite, a one-liner you can use: gdk stop vite rails-web && gdk config set vite.enabled false && gdk config set webpack.enabled true
3. Add a webpack.vue_version = 3 to your gdk.yml
4. gdk reconfigure && gdk restart
5. Confirm you are running Vue 3 on your browser, you can check the console to see the barrage of compat warnings

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1. You can also consider running a full webpack build with: VUE_VERSION=3 yarn webpack-prod

MR acceptance checklist

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Related to #554202 (closed)