Update multipass instructions for single fetch

[wizardlyhel]

WHY are these changes introduced?

Updating the multipass example for single fetch upgrade instruction. This will cause the multipass example to generate this Remix error:

However, this error will go away after a future Remix patch release.

WHAT is this pull request doing?

HOW to test your changes?

Post-merge steps

Checklist

• I've read the Contributing Guidelines
• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've added a changeset if this PR contains user-facing or noteworthy changes
• I've added tests to cover my changes
• I've added or updated the documentation

[shopify]

Oxygen deployed a preview of your hl-fix-multipass-example branch. Details:

Storefront	Status	Preview link	Deployment details	Last update (UTC)
third-party-queries-caching	✅ Successful (Logs)	Preview deployment	Inspect deployment	February 11, 2025 9:45 PM
custom-cart-method	✅ Successful (Logs)	Preview deployment	Inspect deployment	February 11, 2025 9:45 PM
metaobjects	✅ Successful (Logs)	Preview deployment	Inspect deployment	February 11, 2025 9:45 PM
Skeleton (skeleton.hydrogen.shop)	✅ Successful (Logs)	Preview deployment	Inspect deployment	February 11, 2025 9:45 PM
classic-remix	✅ Successful (Logs)	Preview deployment	Inspect deployment	February 11, 2025 9:45 PM

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