Fix remaining Vue.js 2/3 snapshot specs differences

What does this MR do and why?

Related issue: Port custom snapshot serializer for Vue from gi... (#386757 - closed)

This is a follow-up of Implement custom snapshot serializer for Vue.js v3 (!128551 - merged) fixing remaining specs differences

How to set up and validate locally

1. Let's prepare required version of gitlab-ui and merge all required branches (if you're receiving message that some of them does not exists - just skip it)

git merge origin/xanf-fix-ugly-vue
git merge origin/xanf-fix-router-v2
git merge origin/xanf-improve-stubbing-once-again-v2

# install version of gitlab-ui with all needed fixes
yarn add https://gitlab.com/gitlab-org/gitlab-ui/-/jobs/4809835526/artifacts/raw/gitlab-ui.xanf-fix-emptiness-check.tgz

# since this one alters compiler in node_modules drop jest caches 
rm -rf tmp/cache/jest

yarn

1. Run

yarn jest --maxWorkers 6 -u $(grep -rlE 'toMatchSnapshot|toMatchInlineSnapshot' spec/frontend ee/spec/frontend)

This will update all snapshots with latest Vue.js 2 version

2. Run

VUE_VERSION=3 yarn jest --maxWorkers 6 $(grep -rlE 'toMatchSnapshot|toMatchInlineSnapshot' spec/frontend ee/spec/frontend)

Observe jest output where all snapshots matches 🎉

Snapshots:   376 passed, 376 total

MR acceptance checklist

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