Add Central Sandbox URLs for NA and EU

[justinappler]

Description of change

The current Zuora integration supports API sandboxes but not the Central Sandboxes. This change updates the set of possible URLs to include all URLs from this documentation.

Manual QA steps

• Verify integrating with a central sandbox works as well

Risks

• No obvious risks here as all Zuora environments use the same API scheme and the code is designed to handle failures of the URLs and iteration through them gracefully.

Rollback steps

• revert this branch

AI generated code

https://internal.qlik.dev/general/ways-of-working/code-reviews/#guidelines-for-ai-generated-code

• this PR has been written with the help of GitHub Copilot or another generative AI tool

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[justinappler]

@eskaaren @dsprayberry Do changes/improvements to this repo get folded into the Stitch integrations at some cadence? Was trying with this PR to address a breakage in our integration as a result of us moving to a Zuora Central Sandbox which requires the additional URLs added in this PR, and I'm wondering if this is the place to do it?