Polyfill steps missing for Vue.js block switcher

**Describe the content issue**:
A clear and concise description of what the content issue is. Is there content missing or is there incorrect content?

There are steps missing from the Vue.js block switcher instructions for polyfills necessary to avoid build errors. The Angular switcher shows these steps, but they are mising for Vue.

See amplify-js repo issue [#12746](https://github.com/aws-amplify/amplify-js/issues/12746) for more details.

**URL page where content issue is**:

https://docs.amplify.aws/javascript/start/project-setup/create-application/