Fix #135191: Overlay: Edit Mesh: Face selection Z-fighting with edit cage

The offset was not applied inside the vertex shader for
the edit Face selection overlay. Making the offset apply
to this shader fixes the issue.

source/blender/draw/engines/overlay/shaders/overlay_edit_mesh_vert.glsl

@@ -107,9 +107,9 @@ void main()
   finalColor.rgb = mix(finalColor.rgb,
                        non_linear_blend_color(colorEditMeshMiddle.rgb, finalColor.rgb, facing),
                        fresnelMixEdit);
+#endif
 
   gl_Position.z -= ndc_offset_factor * ndc_offset;
-#endif
 
   view_clipping_distances(world_pos);
 }