CustomSelectControlV2: expose legacy wrapper through private APIs

[ciampo]

What?

Part of #55023

Make the CustomSelectControl V2 legacy wrapper available via the component package's private APIs

Why?

So that we can start experimenting with using the new V2 legacy wrapper instead of V1 in the editor, as we prepare for swapping V1 implementation with the V2 legacy wrapper implementation

How?

By exporting the component via locked APIs

Testing Instructions

Make sure that it is possible to import the component via the unlock function from other packages.

[github-actions]

Flaky tests detected in 33d06ce.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/9700511869
📝 Reported issues:

• [Flaky Test] update block style variations in global styles and check revisions match styles #62929 in /test/e2e/specs/site-editor/block-style-variations.spec.js

[github-actions]

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[github-actions]

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Co-authored-by: ciampo <mciampini@git.wordpress.org>
Co-authored-by: tyxla <tyxla@git.wordpress.org>

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[tyxla]

LGTM 👍

Just a minor thought on the naming choice.

[tyxla]

Naming nit: is this really a wrapper though? Since the legacy component isn't really a wrapper as part of a composable component group, but rather a monolithic component, I'd prefer naming this CustomSelectControlV2Legacy or CustomSelectControlV2LegacyAdapter since Wrapper implies a wrapper component in the same way the Tabs parent component wraps the rest of the subcomponents.

No strong feelings about it, but I feel like others might potentially be confused by that naming.

[ciampo]

Good point, pushed an update