I've seen a bathroom where they masked the problem by using the shower wall to hide what in your photo would be the grout line on the left of the narrow strip. You're pretty close to doing that now actually, I didn't even see that grout line in your drawing at first glance. When the glass wall lines up with the grout line it's almost impossible to see what's behind it. Enough light will reflect off the inside surface of the edge of the glass to completely mask whatever's behind it, similar to how the surface of a swimming pool can look like a mirror when viewed from underwater.
In your case, your wall would look like it has three tiles. The middle one would look slightly bigger than the others, but not so much so that it's obvious once the shower walls and mirror are there to break it up. The wall would appear symmetrical since the apparently-larger tile is in the middle, so it doesn't stand out as much as a narrow strip on one end would. If your glass is tinted or frosted at all, then you won't be able to clearly see both sides at once and the illusion should be even more convincing.
This assumes, of course, that the glass extends all the way to the top of the tile as it does in your image. If the tile extends higher than the glass, then the hidden seam will be rather obvious.