### 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.
HashMap<String, bool *> requested_extensions;
	for (OpenXRExtensionWrapper *wrapper : registered_extension_wrappers) {
		const HashMap<String, bool *> &wrapper_request_extensions = wrapper->get_requested_extensions();
		for (const KeyValue<String, bool *> &requested_extension : wrapper_request_extensions) {
			requested_extensions[requested_extension.key] = requested_extension.value;
		}
	}
	
	enabled_extensions.clear();
	for (KeyValue<String, bool *> &requested_extension : requested_extensions) {
		if (!is_extension_supported(requested_extension.key)) {
			if (requested_extension.value == nullptr) {
				
				ERR_FAIL_V_MSG(false, String("OpenXR: OpenXR Runtime does not support ") + requested_extension.key + String(" extension!"));
			} else {
				
				*requested_extension.value = false;
			}
		} else if (requested_extension.value != nullptr) {
			
			*requested_extension.value = true;
			
			enabled_extensions.push_back(requested_extension.key.ascii());
		} else {
			
			enabled_extensions.push_back(requested_extension.key.ascii());
		}
	}