### Godot version

4.2.dev 80de898d721f952dac0b102d48bb73d6b02ee1e8

### System information

OpenXR

### Issue description

The Godot 3 OpenXR plugin supported obtaining boundary/guardian information in order to obtain play space logic. While we do have a function in the `XRInterface` in Godot 4 that is supposed to retrieve this information (`get_play_area`) it is not implemented on the Godot 4 `OpenXRInterface`.

This logic needs to be ported.

### Steps to reproduce

Call `get_play_area`, be amazed by it not returning data :P

### Minimal reproduction project

Any XR project.
class OpenXRAPI {
private:
	
	static OpenXRAPI *singleton;
	
	static Vector<OpenXRExtensionWrapper *> registered_extension_wrappers;
	
	OpenXRInterface *xr_interface = nullptr;
	
	uint32_t num_layer_properties = 0;
	XrApiLayerProperties *layer_properties = nullptr;
	
	uint32_t num_supported_extensions = 0;
	XrExtensionProperties *supported_extensions = nullptr;
	Vector<CharString> enabled_extensions;
	
	Vector<OpenXRCompositionLayerProvider *> composition_layer_providers;
	
	uint32_t num_view_configuration_types = 0;
	XrViewConfigurationType *supported_view_configuration_types = nullptr;
	
	uint32_t num_reference_spaces = 0;
	XrReferenceSpaceType *supported_reference_spaces = nullptr;
	
	uint32_t num_swapchain_formats = 0;
	int64_t *supported_swapchain_formats = nullptr;