### 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_NULL_V(supported_reference_spaces, false);
	for (uint32_t i = 0; i < num_reference_spaces; i++) {
		if (supported_reference_spaces[i] == p_reference_space) {
			return true;
		}
	}
	return false;
}
bool OpenXRAPI::setup_spaces() {
	XrResult result;
	XrPosef identityPose = {
		{ 0.0, 0.0, 0.0, 1.0 },
		{ 0.0, 0.0, 0.0 }
	};
	ERR_FAIL_COND_V(session == XR_NULL_HANDLE, false);
	
	{
		if (!is_reference_space_supported(reference_space)) {
			print_line("OpenXR: reference space ", OpenXRUtil::get_reference_space_name(reference_space), " is not supported.");
			return false;
		}
		XrReferenceSpaceCreateInfo play_space_create_info = {
			XR_TYPE_REFERENCE_SPACE_CREATE_INFO, 
			nullptr,