While we still have the one in our Milano, we disconnected it, as we found that it tended to empty the fluid tank at a prodigious rate. Too fast for us, when we would rather have enough wiper fluid instead. Besides, we found that the headlight spray didn't really clean the headlights work a darn. A paper towel run over the headlights once in a while is infinitely better.
In other words, I wouldn't bother, just disconnect the wiring for that pump and seal the hole in the hose.
This is similar to the headlight washers for the 1991-93 164, as they don't work after a while, the little rising nozzles jamming from bad wear after a few uses. We just disconnected that wiring and plugged the line.