### 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.
ERR_FAIL_COND_V(instance == XR_NULL_HANDLE, false);
	ERR_FAIL_COND_V(session != XR_NULL_HANDLE, false);
	void *next_pointer = nullptr;
	for (OpenXRExtensionWrapper *wrapper : registered_extension_wrappers) {
		void *np = wrapper->set_session_create_and_get_next_pointer(next_pointer);
		if (np != nullptr) {
			next_pointer = np;
		}
	}
	XrSessionCreateInfo session_create_info = {
		XR_TYPE_SESSION_CREATE_INFO, 
		next_pointer, 
		0, 
		system_id 
	};
	XrResult result = xrCreateSession(instance, &session_create_info, &session);
	if (XR_FAILED(result)) {
		print_line("OpenXR: Failed to create session [", get_error_string(result), "]");
		return false;
	}
	for (OpenXRExtensionWrapper *wrapper : registered_extension_wrappers) {
		wrapper->on_session_created(session);
	}
	return true;
}
bool OpenXRAPI::load_supported_reference_spaces() {