### 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);
	if (supported_environment_blend_modes != nullptr) {
		
		memfree(supported_environment_blend_modes);
		supported_environment_blend_modes = nullptr;
		num_supported_environment_blend_modes = 0;
	}
	XrResult result = xrEnumerateEnvironmentBlendModes(instance, system_id, view_configuration, 0, &num_supported_environment_blend_modes, nullptr);
	if (XR_FAILED(result)) {
		print_line("OpenXR: Failed to get supported environmental blend mode count [", get_error_string(result), "]");
		return false;
	}
	supported_environment_blend_modes = (XrEnvironmentBlendMode *)memalloc(sizeof(XrEnvironmentBlendMode) * num_supported_environment_blend_modes);
	ERR_FAIL_NULL_V(supported_environment_blend_modes, false);
	result = xrEnumerateEnvironmentBlendModes(instance, system_id, view_configuration, num_supported_environment_blend_modes, &num_supported_environment_blend_modes, supported_environment_blend_modes);
	ERR_FAIL_COND_V_MSG(XR_FAILED(result), false, "OpenXR: Failed to enumerate environmental blend modes");
	ERR_FAIL_COND_V_MSG(num_supported_environment_blend_modes == 0, false, "OpenXR: Failed to enumerate environmental blend modes"); 
	for (uint32_t i = 0; i < num_supported_environment_blend_modes; i++) {
		print_verbose(String("OpenXR: Found environmental blend mode ") + OpenXRUtil::get_environment_blend_mode_name(supported_environment_blend_modes[i]));
	}
	
	if (!is_environment_blend_mode_supported(environment_blend_mode)) {
		print_verbose(String("OpenXR: ") + OpenXRUtil::get_environment_blend_mode_name(environment_blend_mode) + String(" isn't supported, defaulting to ") + OpenXRUtil::get_environment_blend_mode_name(supported_environment_blend_modes[0]));
		environment_blend_mode = supported_environment_blend_modes[0];
	}
	return true;
}
bool OpenXRAPI::is_view_configuration_supported(XrViewConfigurationType p_configuration_type) const {