### 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_MSG(instance != XR_NULL_HANDLE, false, "OpenXR instance was already created");
	if (!openxr_loader_init()) {
		return false;
	}
	if (p_rendering_driver == "vulkan") {
#ifdef VULKAN_ENABLED
		graphics_extension = memnew(OpenXRVulkanExtension);
		register_extension_wrapper(graphics_extension);
#else
		
		ERR_FAIL_V(false);
#endif
	} else if (p_rendering_driver == "opengl3") {
#if defined(GLES3_ENABLED) && !defined(MACOS_ENABLED)
		graphics_extension = memnew(OpenXROpenGLExtension);
		register_extension_wrapper(graphics_extension);
#else
		
		ERR_FAIL_V(false);
#endif
	} else {
		ERR_FAIL_V_MSG(false, "OpenXR: Unsupported rendering device.");
	}