fix: decompress body from edge functions errors

[eduardoboucas]

Summary

Right now, if an edge function throws an unhandled exception, the CLI will crash with a cryptic error message:

SyntaxError: Unexpected token  in JSON at position 0
    at JSON.parse (<anonymous>)
    at formatEdgeFunctionError (file:///Users/eduardoboucas/Sites/netlify/cli/src/utils/proxy.mjs:65:12)
    at IncomingMessage.onEnd (file:///Users/eduardoboucas/Sites/netlify/cli/src/utils/proxy.mjs:548:31)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)

This is because the edge function is sending a compressed response which the CLI needs to decompress. We do have some logic for checking whether the body needs to be decompressed, which we've added in #5837, but we're reading the accept-encoding header from the incoming request, when we should be reading it from the response we get from the Deno server.

[github-actions]

📊 Benchmark results

Comparing with 3dcae88

• Dependency count: 1,365 (no change)
• Package size: 366 MB ⬇️ 0.00% decrease vs. 3dcae88

[lukasholzer]

LGTM!