### 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.
composition_layer_providers.append(provider);
}
void OpenXRAPI::unregister_composition_layer_provider(OpenXRCompositionLayerProvider *provider) {
	composition_layer_providers.erase(provider);
}
const XrEnvironmentBlendMode *OpenXRAPI::get_supported_environment_blend_modes(uint32_t &count) {
	count = num_supported_environment_blend_modes;
	return supported_environment_blend_modes;
}
bool OpenXRAPI::is_environment_blend_mode_supported(XrEnvironmentBlendMode p_blend_mode) const {
	ERR_FAIL_NULL_V(supported_environment_blend_modes, false);
	for (uint32_t i = 0; i < num_supported_environment_blend_modes; i++) {
		if (supported_environment_blend_modes[i] == p_blend_mode) {
			return true;
		}
	}
	return false;
}
bool OpenXRAPI::set_environment_blend_mode(XrEnvironmentBlendMode p_blend_mode) {
	
	
	if (!is_initialized() || is_environment_blend_mode_supported(p_blend_mode)) {
		environment_blend_mode = p_blend_mode;
		return true;
	}
	return false;
}