### 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(session == XR_NULL_HANDLE, false);
	if (supported_reference_spaces != nullptr) {
		
		memfree(supported_reference_spaces);
		supported_reference_spaces = nullptr;
	}
	XrResult result = xrEnumerateReferenceSpaces(session, 0, &num_reference_spaces, nullptr);
	if (XR_FAILED(result)) {
		print_line("OpenXR: Failed to get reference space count [", get_error_string(result), "]");
		return false;
	}
	supported_reference_spaces = (XrReferenceSpaceType *)memalloc(sizeof(XrReferenceSpaceType) * num_reference_spaces);
	ERR_FAIL_NULL_V(supported_reference_spaces, false);
	result = xrEnumerateReferenceSpaces(session, num_reference_spaces, &num_reference_spaces, supported_reference_spaces);
	ERR_FAIL_COND_V_MSG(XR_FAILED(result), false, "OpenXR: Failed to enumerate reference spaces");
	ERR_FAIL_COND_V_MSG(num_reference_spaces == 0, false, "OpenXR: Failed to enumerate reference spaces");
	for (uint32_t i = 0; i < num_reference_spaces; i++) {
		print_verbose(String("OpenXR: Found supported reference space ") + OpenXRUtil::get_reference_space_name(supported_reference_spaces[i]));
	}
	
	if (!is_reference_space_supported(reference_space)) {
		print_verbose(String("OpenXR: ") + OpenXRUtil::get_reference_space_name(reference_space) + String(" isn't supported, defaulting to ") + OpenXRUtil::get_reference_space_name(supported_reference_spaces[0]));
		reference_space = supported_reference_spaces[0];
	}
	return true;
}
bool OpenXRAPI::is_reference_space_supported(XrReferenceSpaceType p_reference_space) {