docs: remove mention of beta

[Josh-Cena]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes Docs still mention beta #7903) and the maintainers have approved on my working plan.

Motivation

Also removed a few outdated dependencies that are duplicated from the prod dependencies and failed to be bumped

Test Plan

Test links

Deploy preview: https://deploy-preview-_____--docusaurus-2.netlify.app/

Related issues/PRs

[Josh-Cena]

Adding the https://github.com/facebook/docusaurus/labels/backport because obviously the v2 package.json need to be fixed as well

[netlify]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 80	🟢 98	🟢 100	🟢 100	🟠 80	Report
/docs/installation	🟠 86	🟢 100	🟢 100	🟢 100	🟢 90	Report

[github-actions]

Size Change: 0 B

Total Size: 812 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	52.5 kB
website/build/assets/css/styles.********.css	111 kB
website/build/assets/js/main.********.js	608 kB
website/build/index.html	40.7 kB

_{compressed-size-action}

[slorber]

LGTM

I'd rather have this in 2 separate PRs next time:

• clearer pr title, nothing hidden in the impl details
• probably also easier to backport/cherry-pick?