No bounds checking inside Match Types

## Compiler version

https://github.com/scala/scala3/commit/d20dd28f79fd6bdbf77d78af5c55ec5e08350c4a

## Minimized code

```scala
type S[N <: Int]

type Foo[Xs] = Xs match
  case _ => S[String]
```

## Output

Compiles

## Expectation

Clearly, I cannot create an `S[String]` since `String <: Int` is false.
