refactor(theme-common): rename useDynamicCallback to useEvent

[slorber]

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 #0000) and the maintainers have approved on my working plan.

Motivation

Follow-up of #7660

Rename useDynamicCallback to useEvent as it's more likely to be named that way in React core (see reactjs/rfcs#220)

Not considering this as a breaking change considering we just created the public API surface (+ it's mostly used internally in theme-common)

Test Plan

Test links

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

Related issues/PRs

[Josh-Cena]

It's likely slightly different from useEvent (in terms of update timing, for example; although I don't think that's finalized yet). Would it create confusion for external users?

[netlify]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 70	🟢 100	🟢 100	🟢 100	🟢 90	Report
/docs/installation	🟠 84	🟢 100	🟢 100	🟢 100	🟢 90	Report

[github-actions]

Size Change: 0 B

Total Size: 802 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	52.6 kB
website/build/assets/css/styles.********.css	107 kB
website/build/assets/js/main.********.js	604 kB
website/build/index.html	38.9 kB

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[slorber]

It's likely slightly different from useEvent (in terms of update timing, for example; although I don't think that's finalized yet). Would it create confusion for external users?

We'll replace it with useEvent() once released anyway and the small differences are for quite specific edge cases.

We can simply document this as a temporary userland implementation until the official hook is released. In any case the user should be aware of the potential limitations of the userland implementation, as explained in the RFC.