### 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.
if (supported_extensions != nullptr) {
		
		return true;
	}
	
	XrResult result = xrEnumerateInstanceExtensionProperties(nullptr, 0, &num_supported_extensions, nullptr);
	ERR_FAIL_COND_V_MSG(XR_FAILED(result), false, "OpenXR: Failed to enumerate number of extension properties");
	supported_extensions = (XrExtensionProperties *)memalloc(sizeof(XrExtensionProperties) * num_supported_extensions);
	ERR_FAIL_NULL_V(supported_extensions, false);
	
	for (uint32_t i = 0; i < num_supported_extensions; i++) {
		supported_extensions[i].type = XR_TYPE_EXTENSION_PROPERTIES;
		supported_extensions[i].next = nullptr;
	}
	result = xrEnumerateInstanceExtensionProperties(nullptr, num_supported_extensions, &num_supported_extensions, supported_extensions);
	ERR_FAIL_COND_V_MSG(XR_FAILED(result), false, "OpenXR: Failed to enumerate extension properties");
	for (uint32_t i = 0; i < num_supported_extensions; i++) {
		print_verbose(String("OpenXR: Found OpenXR extension ") + supported_extensions[i].extensionName);
	}
	return true;
}
bool OpenXRAPI::is_extension_supported(const String &p_extension) const {