Fix leaking props in SubdomainNavBar to remove warning from unit tests

[joshfarrant]

Summary

Fixes props which were leaking into the DOM, both in Storybook and in the SubdomainNavBar component itself.

List of notable changes:

• Explicitly destructured props in SubdomainNavBar.stories.tsx to prevent props leaking into the DOM of rendered story.
• Removed unused showOnlyOnNarrow prop from SubdomainNavBar.tsx to prevent it leaking into the DOM and to fix a related warning in the unit tests.

What should reviewers focus on?

• I can't see the showOnlyOnNarrow prop being used anywhere, and I'm not sure it was ever implemented since being added in SubdomainNavBar overflow fix #451. Another set of eyes on this would be appreciated though.
• Check that the SubdomainNavBar still works in the expected way.

Contributor checklist:

• All new and existing CI checks pass
• Tests prove that the feature works and covers both happy and unhappy paths
• Any drop in coverage, breaking changes or regressions have been documented above
• UI Changes contain new visual snapshots (generated by adding update snapshots label to the PR)
• All developer debugging and non-functional logging has been removed
• Related issues have been referenced in the PR description

Reviewer checklist:

• Check that pull request and proposed changes adhere to our contribution guidelines and code of conduct
• Check that tests prove the feature works and covers both happy and unhappy paths
• Check that there aren't other open Pull Requests for the same update/change

Screenshots:

Before	After

[changeset-bot]

🦋 Changeset detected

Latest commit: bf8c2d5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 8 packages

Name	Type
@primer/react-brand	Patch
@primer/brand-docs	Patch
@primer/brand-css	Patch
@primer/brand-primitives	Patch
@primer/brand-e2e	Patch
@primer/brand-fonts	Patch
@primer/brand-config	Patch
@primer/brand-storybook	Patch

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[github-actions]

🟢 No design token changes found

[Copilot]

Pull Request Overview

This PR prevents unwanted props from appearing in the DOM by removing an unused prop from the component and explicitly destructuring story args.

• Removed the unused showOnlyOnNarrow prop from SubdomainNavBar.
• Updated the Storybook template to destructure and exclude showSearch and numLinks.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/react/src/SubdomainNavBar/SubdomainNavBar.tsx	Removed the showOnlyOnNarrow prop so it no longer leaks into the rendered DOM.
packages/react/src/SubdomainNavBar/SubdomainNavBar.stories.tsx	Destructured showSearch and numLinks in the Template signature to avoid prop leakage.

Comments suppressed due to low confidence (1)

packages/react/src/SubdomainNavBar/SubdomainNavBar.tsx:322

• The showOnlyOnNarrow prop was removed from the JSX, but the component's prop interface and any related documentation or tests may still reference it. Consider cleaning up the SubdomainNavBarProps type and removing any mentions of showOnlyOnNarrow to keep the API contract consistent.

                    )}

[github-actions]

🟢 No visual differences found

Our visual comparison tests did not find any differences in the UI.

[rezrah]

Oh wow, so this wasn't doing anything at all? 😬

[joshfarrant]

No I don't believe so 😅