Fix the incorrect process of converting ArrayBuffer to base64

[Karibash]

I made a silly mistake...

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🦋 Changeset detected

Latest commit: 61868c812e10390eb819e067714f445f0ec792d8

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

This PR includes changesets to release 1 package

| Name | Type | | ----------------- | ----- | | cf-bindings-proxy | Patch |

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🧪 A prerelease is available for testing 🧪

You can install this latest build in your project with: ```sh npm install --save-dev https://prerelease-registry.ixion-labs.workers.dev/james-elicx/cf-bindings-proxy/runs/5974365720/npm-package-cf-bindings-proxy-27 ``` Or you can immediately run this with `npx`: ```sh npx https://prerelease-registry.ixion-labs.workers.dev/james-elicx/cf-bindings-proxy/runs/5974365720/npm-package-cf-bindings-proxy-27 ```