### Godot version

4.0.rc6.mono.official

### System information

macOS 12.0.1

### Issue description

Just a minor visual issue.

When opening an empty directory the focus highlight is drawn incorrectly. It looks like the UI is drawing a smaller rectangle within the main rect:
<img width="1058" alt="Bildschirmfoto 2023-02-28 um 14 13 31" src="https://user-images.githubusercontent.com/11627131/221868794-7450606d-e758-4104-8f33-182d9779d7f8.png">


This behavior also changes when you hover over other items in the view, so I'm not sure if this a general issue with the focus highlighting or just an issue in the directory view:
<img width="1052" alt="Bildschirmfoto 2023-02-28 um 14 32 54" src="https://user-images.githubusercontent.com/11627131/221869308-4756f26e-cda2-4057-be1e-7439030895dc.png">


### Steps to reproduce

1. New Project
2. Browse
3. Create Folder
4. Click or Tab to set focus on the empty directory view

### Minimal reproduction project

N/A
GLES3::MaterialStorage *material_storage = GLES3::MaterialStorage::get_singleton();
	canvas_begin(p_to_render_target, p_to_backbuffer);
	if (p_item_count <= 0) {
		
		return;
	}
	uint32_t index = 0;
	Item *current_clip = nullptr;
	GLES3::CanvasShaderData *shader_data_cache = nullptr;
	
	
	bool batch_broken = false;
	_new_batch(batch_broken);
	
	state.canvas_instance_batches[state.current_batch_index].start = state.last_item_index;
	index = 0;
	for (int i = 0; i < p_item_count; i++) {
		Item *ci = items[i];
		if (ci->final_clip_owner != state.canvas_instance_batches[state.current_batch_index].clip) {
			_new_batch(batch_broken);
			state.canvas_instance_batches[state.current_batch_index].clip = ci->final_clip_owner;
			current_clip = ci->final_clip_owner;
		}
		RID material = ci->material_owner == nullptr ? ci->material : ci->material_owner->material;
		if (ci->use_canvas_group) {
			if (ci->canvas_group->mode == RS::CANVAS_GROUP_MODE_CLIP_AND_DRAW) {
				material = default_clip_children_material;
			} else {