### 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.
case 0: {
				form_factor = XR_FORM_FACTOR_HEAD_MOUNTED_DISPLAY;
			} break;
			case 1: {
				form_factor = XR_FORM_FACTOR_HANDHELD_DISPLAY;
			} break;
			default:
				break;
		}
		int view_configuration_setting = GLOBAL_GET("xr/openxr/view_configuration");
		switch (view_configuration_setting) {
			case 0: {
				view_configuration = XR_VIEW_CONFIGURATION_TYPE_PRIMARY_MONO;
			} break;
			case 1: {
				view_configuration = XR_VIEW_CONFIGURATION_TYPE_PRIMARY_STEREO;
			} break;
			/* we don't support quad and observer configurations (yet)
			case 2: {
				view_configuration = XR_VIEW_CONFIGURATION_TYPE_PRIMARY_QUAD_VARJO;
			} break;
			case 3: {
				view_configuration = XR_VIEW_CONFIGURATION_TYPE_SECONDARY_MONO_FIRST_PERSON_OBSERVER_MSFT;
			} break;
			*/
			default:
				break;
		}
		int reference_space_setting = GLOBAL_GET("xr/openxr/reference_space");
		switch (reference_space_setting) {