### 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
CanvasLight *cl = canvas_light_owner.get_or_null(p_rid);
	ERR_FAIL_NULL(cl);
	cl->shadow.enabled = p_enable;
}
void RasterizerCanvasGLES3::light_update_shadow(RID p_rid, int p_shadow_index, const Transform2D &p_light_xform, int p_light_mask, float p_near, float p_far, LightOccluderInstance *p_occluders) {
	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();
	cl->shadow.z_far = p_far;
	cl->shadow.y_offset = float(p_shadow_index * 2 + 1) / float(data.max_lights_per_render * 2);
	glBindFramebuffer(GL_FRAMEBUFFER, state.shadow_fb);
	glViewport(0, p_shadow_index * 2, state.shadow_texture_size, 2);
	glDepthMask(GL_TRUE);
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LESS);
	glDisable(GL_BLEND);
	glEnable(GL_SCISSOR_TEST);
	glScissor(0, p_shadow_index * 2, state.shadow_texture_size, 2);
	glClearColor(p_far, p_far, p_far, 1.0);
	RasterizerGLES3::clear_depth(1.0);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glCullFace(GL_BACK);
	glDisable(GL_CULL_FACE);