fix: b64-encode geo location in local dev

[Skn0tt]

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Summary

Part of https://github.com/netlify/pod-dev-foundations/issues/558. Makes sure that the geo location is encoded as b64 before being passed into headers, similar to how we'll do it in prod.

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[github-actions]

📊 Benchmark results

Comparing with 2c9d8f9

• Dependency count: 1,320 ⬆️ 1.59% increase vs. 2c9d8f9
• Package size: 275 MB ⬆️ 1.64% increase vs. 2c9d8f9

[lukasholzer]

LGTM

[eduardoboucas]

Did you mean to include a ZISI update as part of this?

[Skn0tt]

yes, because that contains the updated @netlify/serverless-functions-api