Fix Vue 3 spec email_verification_spec

What does this MR do and why?

Fix Vue 3 failing test

Add waitForPromises

Vue 3 has 2 ticks as email_verification.vue explicitly use this.$nextTick

MR acceptance checklist

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How to set up and validate locally

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

1. Run test locally VUE_VERSION=3 yarn jest path-to-spec
2. Checkout branch
3. Run test locally VUE_VERSION=3 yarn jest path-to-spec

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Related to #522029 (closed)