chore: remove redundant async in readable.js

[Uzlopak]

fixes #3610

We dont need to wrap non awaited Promises/async calls.

[mcollina]

Is this improving anything? This will worsen the DX as .json() will disappear from the stacktrace.

[Uzlopak]

Let me check the stack traces.

[Uzlopak]

@mcollina

'use strict'

const { Client } = require('./index')

async function run() {
    const client = new Client('https://www.google.com')
    const { body } = await client.request({
      path: '/',
      method: 'GET'
    })
    console.log(await body.json())
    client.destroy()
}

run()

In both branches I get:

SyntaxError: Unexpected token < in JSON at position 0
    at JSON.parse (<anonymous>)
    at consumeEnd (/home/aras/undici/lib/api/readable.js:505:20)
    at BodyReadable.<anonymous> (/home/aras/undici/lib/api/readable.js:429:7)
    at BodyReadable.emit (node:events:517:28)
    at endReadableNT (node:internal/streams/readable:1400:12)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21)

[Uzlopak]

@mcollina

Can I merge?

[mcollina]

lgtm