chore(v2): Fix Crowdin 409 issues in CI

[slorber]

Motivation

Crowdin does not support concurrency well, and emit 409 errors in case of concurrent translation downloads

We have 2 Netlify deployments triggered on each PR merge: prod and i18n staging.

One of them often resulting in a 409 error.

And the prod website may not deploy immediately, which can be annoying after a new release (see #4702)

Solution: a node script to wait for Crowdin API to report there is no build in progress (ie, it's safe to download the translations)

Note: I think concurrent uploads can also lead to 409 errors but it is less frequent (upload is generally faster)

Have you read the Contributing Guidelines on pull requests?

yes

Test Plan

CI

[netlify]

[V2]

Built with commit 2da28c1

https://deploy-preview-4739--docusaurus-2.netlify.app

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	60
🟢 Accessibility	96
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-4739--docusaurus-2.netlify.app/

[netlify]

[V1]

Built with commit 2da28c1

https://deploy-preview-4739--docusaurus-1.netlify.app

[github-actions]

Size Change: 0 B

Total Size: 691 kB

ℹ️ View Unchanged

Filename	Size	Change
website/build/assets/css/styles.********.css	88.5 kB	0 B
website/build/assets/js/main.********.js	513 kB	0 B
website/build/blog/2017/12/14/introducing-docusaurus/index.html	62.1 kB	0 B
website/build/docs/introduction/index.html	235 B	0 B
website/build/index.html	27.1 kB	0 B

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