Svelte 5: $effect async callback type missing TypeScript

[codeit-ninja]

Describe the bug

When passing a async callback in $effect, causes error.

Example:

$effect( async () => {
   // ... code
})

Reproduction

let count = $state(0);

$effect( async () => {
	const request = await fetch('https://dummyjson.com/products/1')
	const json = await request.json()
		
	console.log(json)
})

### Logs

_No response_

### System Info

```shell
System:
    OS: Linux 5.15 Ubuntu 22.04.2 LTS 22.04.2 LTS (Jammy Jellyfish)
    CPU: (16) x64 AMD Ryzen 7 5800X3D 8-Core Processor
    Memory: 10.00 GB / 15.58 GB
    Container: Yes
    Shell: 5.1.16 - /bin/bash
  Binaries:
    Node: 20.9.0 - ~/.volta/tools/image/node/20.9.0/bin/node
    Yarn: 4.0.1 - ~/.volta/tools/image/yarn/4.0.1/bin/yarn
    npm: 10.1.0 - ~/.volta/tools/image/node/20.9.0/bin/npm
    bun: 1.0.18 - ~/.bun/bin/bun
  Browsers:
    Chrome: 117.0.5938.88
  npmPackages:
    svelte: 5.0.0-next.25

Severity

annoyance

[PuruVJ]

AFAIK, $effect doesn't accept async function as callback. Solution is to declare an async function inside the $effect callback and call that function

[Conduitry]

Duplicate of #9520. It is intentional that the types do not admit an asynchronous function.