### 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
glDrawArraysInstanced(prim[polygon->primitive], 0, pb->count, 1);
			}
			glBindVertexArray(0);
			if (pb->color_disabled && pb->color != Color(1.0, 1.0, 1.0, 1.0)) {
				
				glVertexAttrib4f(RS::ARRAY_COLOR, 1.0, 1.0, 1.0, 1.0);
			}
		} break;
		case Item::Command::TYPE_PRIMITIVE: {
			glBindVertexArray(data.canvas_quad_array);
			glBindBuffer(GL_ARRAY_BUFFER, state.canvas_instance_data_buffers[state.current_data_buffer_index].instance_buffers[state.canvas_instance_batches[p_index].instance_buffer_index]);
			uint32_t range_start = state.canvas_instance_batches[p_index].start * sizeof(InstanceData);
			_enable_attributes(range_start, true);
			const GLenum primitive[5] = { GL_POINTS, GL_POINTS, GL_LINES, GL_TRIANGLES, GL_TRIANGLES };
			int instance_count = state.canvas_instance_batches[p_index].instance_count;
			ERR_FAIL_COND(instance_count <= 0);
			if (instance_count >= 1) {
				glDrawArraysInstanced(primitive[state.canvas_instance_batches[p_index].primitive_points], 0, state.canvas_instance_batches[p_index].primitive_points, instance_count);
			}
		} break;
		case Item::Command::TYPE_MESH:
		case Item::Command::TYPE_MULTIMESH:
		case Item::Command::TYPE_PARTICLES: {
			GLES3::MeshStorage *mesh_storage = GLES3::MeshStorage::get_singleton();
			GLES3::ParticlesStorage *particles_storage = GLES3::ParticlesStorage::get_singleton();
			RID mesh;
			RID mesh_instance;
			uint32_t instance_count = 1;
			GLuint instance_buffer = 0;
			uint32_t instance_stride = 0;