### 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 (submit_depth_buffer && OpenXRCompositionLayerDepthExtension::get_singleton()->is_available()) {
		
		Vector<int64_t> usable_swapchain_formats;
		int64_t swapchain_format_to_use = 0;
		graphics_extension->get_usable_depth_formats(usable_swapchain_formats);
		
		for (int i = 0; i < usable_swapchain_formats.size() && swapchain_format_to_use == 0; i++) {
			if (is_swapchain_format_supported(usable_swapchain_formats[i])) {
				swapchain_format_to_use = usable_swapchain_formats[i];
			}
		}
		if (swapchain_format_to_use == 0) {
			print_line("Couldn't find usable depth swap chain format, depth buffer will not be submitted.");
		} else {
			print_verbose(String("Using depth swap chain format:") + get_swapchain_format_name(swapchain_format_to_use));
			
			if (!create_swapchain(XR_SWAPCHAIN_USAGE_SAMPLED_BIT | XR_SWAPCHAIN_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT, swapchain_format_to_use, recommended_size.width, recommended_size.height, sample_count, view_count, swapchains[OPENXR_SWAPCHAIN_DEPTH].swapchain, &swapchains[OPENXR_SWAPCHAIN_DEPTH].swapchain_graphics_data)) {
				return false;
			}
			depth_views = (XrCompositionLayerDepthInfoKHR *)memalloc(sizeof(XrCompositionLayerDepthInfoKHR) * view_count);
			ERR_FAIL_NULL_V_MSG(depth_views, false, "OpenXR Couldn't allocate memory for depth views");
		}
	}
	
	
	{
		
	}