fix(payments-next): UpgradeCartFromOfferingConfigIdMissingError: from OfferingConfigId not present for upgrade cart

[elizabeth-ilina]

Because

• If customer goes through the upgrade flow and lands on the success page then navigates back to start, the cart will be missing the fromOfferingConfigId, throwing an error and showing the "something went wrong" page.

This pull request

• Uses getCartOrRedirectAction instead of getCartAction in [locale]/[offeringId]/[interval]/upgrade/[cartId]/(startLayout)/layout.tsx

Issue that this pull request solves

Closes #PAY-3705

Checklist

Put an x in the boxes that apply

• My commit is GPG signed.
• If applicable, I have modified or added tests which pass locally.
• I have added necessary documentation (if appropriate).
• I have verified that my changes render correctly in RTL (if appropriate).
• I have manually reviewed all AI generated code.

How to review (Optional)

STRs:

1. Subscribe to (for example) VPN monthly.
2. Upgrade (successfully) to yearly.
3. Either: press the 'back' arrow from the success page, OR, edit the URL to be start instead of success (both videos attached).

In Stage, pressing the 'back' arrow:

Screen.Recording.2026-05-25.at.11.05.17.AM.mov

Or, editing the URL:

Screen.Recording.2026-05-25.at.11.49.50.AM.mov

After fix:

Screen.Recording.2026-05-25.at.11.51.45.AM.mov

• Key files/areas to focus on:
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Please attach the screenshots of the changes made in case of change in user interface.

Other information (Optional)

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