Composite: deprecate legacy, unstable version

[ciampo]

What?

Requires #63564 and #63569
Part of #58850

Deprecate the legacy, unstable version of the Composite component.

Why?

See #58850

How?

• Added JSDocs and runtime warnings
• Added unit tests

Testing Instructions

• Since there are no usages left of the unstable component, there shouldn't be any runtime changes;
• Make sure that changes in the JSDocs are reflected correctly in modern IDEs
• Make sure that deprecation warnings are outputted as expected in the console

[github-actions]

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Co-authored-by: ciampo <[email protected]>
Co-authored-by: tyxla <[email protected]>

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[tyxla]

LGTM 👍

Still tests well in Storybook.

Besides this one, what do we need to be able to close #58850? Just a dev note?

[ciampo]

Besides this one, what do we need to be able to close #58850? Just a dev note?

I closed #58850 and added a dev note to #63569