### 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::Config *config = GLES3::Config::get_singleton();
	CanvasLight *cl = canvas_light_owner.get_or_null(p_rid);
	ERR_FAIL_COND(!cl->shadow.enabled);
	_update_shadow_atlas();
	Vector2 light_dir = p_light_xform.columns[1].normalized();
	Vector2 center = p_clip_rect.get_center();
	float to_edge_distance = ABS(light_dir.dot(p_clip_rect.get_support(light_dir)) - light_dir.dot(center));
	Vector2 from_pos = center - light_dir * (to_edge_distance + p_cull_distance);
	float distance = to_edge_distance * 2.0 + p_cull_distance;
	float half_size = p_clip_rect.size.length() * 0.5; 
	cl->shadow.z_far = distance;
	cl->shadow.y_offset = float(p_shadow_index * 2 + 1) / float(data.max_lights_per_render * 2);
	Transform2D to_light_xform;
	to_light_xform[2] = from_pos;
	to_light_xform[1] = light_dir;
	to_light_xform[0] = -light_dir.orthogonal();
	to_light_xform.invert();
	glBindFramebuffer(GL_FRAMEBUFFER, state.shadow_fb);
	glViewport(0, p_shadow_index * 2, state.shadow_texture_size, 2);
	glDepthMask(GL_TRUE);