### 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
state.canvas_instance_batches[state.current_batch_index].instance_count++;
	r_index++;
	if (r_index + state.last_item_index >= data.max_instances_per_buffer) {
		
		
		glBindBuffer(GL_ARRAY_BUFFER, state.canvas_instance_data_buffers[state.current_data_buffer_index].instance_buffers[state.current_instance_buffer_index]);
#ifdef WEB_ENABLED
		glBufferSubData(GL_ARRAY_BUFFER, state.last_item_index * sizeof(InstanceData), sizeof(InstanceData) * r_index, state.instance_data_array);
#else
		
		void *buffer = glMapBufferRange(GL_ARRAY_BUFFER, state.last_item_index * sizeof(InstanceData), r_index * sizeof(InstanceData), GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT);
		memcpy(buffer, state.instance_data_array, r_index * sizeof(InstanceData));
		glUnmapBuffer(GL_ARRAY_BUFFER);
#endif
		_allocate_instance_buffer();
		r_index = 0;
		state.last_item_index = 0;
		r_batch_broken = false; 
		_new_batch(r_batch_broken);
		state.canvas_instance_batches[state.current_batch_index].start = 0;
	}
}
void RasterizerCanvasGLES3::_new_batch(bool &r_batch_broken) {