Fixes display of long site title on mobile

[techfg]

Description

• Closes site title/logo extends beyond menu toggle and search button not visible on mobile view #2715
• What does this PR change? Ensure that when site title logo/text extends beyond viewport, the search icon is visible and the mobile menu toggle does not overlay the site title text/logo.
• Did you change something visual? A before/after screenshot can be helpful.

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🦋 Changeset detected

Latest commit: 3ff3855

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

This PR includes changesets to release 1 package

Name	Type
@astrojs/starlight	Patch

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Lighthouse	1 paths audited Performance: 100 (no change from production) Accessibility: 100 (no change from production) Best Practices: 100 (no change from production) SEO: 100 (no change from production) PWA: - View the detailed breakdown and full score reports

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