`PlaneDetectorEXT::getPlaneDetectionStateEXT` still broken

The enhanced function contains this code

```
XrPlaneDetectionStateEXT state_tmp;
PlaneDetectionStateEXT state;
Result result = static_cast(
d.xrGetPlaneDetectionStateEXT(this->get(), state_tmp));
```

But the dispatcher call here expects a `XrPlaneDetectionStateEXT*` as it's second argument, not a `XrPlaneDetectionStateEXT`.

Start at PlaneDetectorEXT::getPlaneDetectionStateEXT and compare its dispatcher call with the xrGetPlaneDetectionStateEXT declaration, which expects a pointer for the state argument. Update the call so it matches that interface, then confirm the C++ projection builds successfully.

Written by the indexing model from the issue text.