Inconsistent behavior with Generic ElementType

### 🔎 Search Terms

JSX, Generic ElementType, TS2786

### 🕗 Version & Regression Information

- Behavior seen in 5.8.3 and 5.9.0-dev.20250703
- I was unable to test this on prior versions

### ⏯ Playground Link

_No response_

### 💻 Code

```ts
export namespace dsl {
export namespace JSX {
export type Element = {
name: U
type: string
children: Element[]
}

[tsconfig.json](https://github.com/user-attachments/files/21047590/tsconfig.json)

export function createElement(
tag: JSX.ElementType,
props : { name: U },
...children: JSX.Element[]
): JSX.Element {
return tag(props, ...children)
}
}

function Form(props: { name: U }, ...children: dsl.JSX.Element[]) {
return { ...props, type: "form", children }
}

const formDesugared = dsl.createElement(
Form, { name: "one" }
)

const form = (
// <--- Error here, error TS2786: 'Form' cannot be used as a JSX component.
)

```

### 🙁 Actual behavior

Compile error:

sui.tsx:31:6 - error TS2786: 'Form' cannot be used as a JSX component.
Its type '(props: { name: U; }, ...children: Element[]) => { type: string; children: Element[]; name: U; }' is not a valid JSX element type.
Types of parameters 'props' and 'props' are incompatible.
Type '{ name: unknown; }' is not assignable to type '{ name: string; }'.
Types of property 'name' are incompatible.
Type 'unknown' is not assignable to type 'string'.

31

### 🙂 Expected behavior

Changing props: { name: U } in the definition of ElementType to props: { name: string } causes the code to compile [loosing the wanted typing of the resulting Element

Since the desugared version of the code compiles and infers types correctly, I'd expect the JSX code to compile, or at least produce a less deeply mysterious error - the type of the 'name' property plainly *isn't* unknown.

### Additional information about the issue

_No response_

Reproduce el ejemplo .tsx con el tsconfig.json enlazado en TypeScript 5.8.3 y en la versión de desarrollo 5.9, comparando JSX con dsl.createElement y el diagnóstico TS2786. Traza cómo JSX.ElementType comprueba el genérico Form; se considera terminado cuando la forma JSX compila de manera consistente con la llamada desazucarada, conserva la tipificación inferida prevista de Element y evita el error engañoso de nombre desconocido.

Escrito por el modelo de indexación a partir del texto del issue.