Trying to query a `ng-template` with `CdkPortalOutlet` is always unsuccessful, and I cant understand why?

```
<ng-template CdkPortalOutlet></ng-template>

@ViewChild(CdkPortalOutlet) test: CdkPortalOutlet;

```

[stackblitz](https://stackblitz.com/edit/cdk-overlays-68dss7)