Ide like to add a t-piece to incorporate the sensor and monitor the vacuum for variation over time and failure.
So you want to "break" the vacuum system, and in effect, introduce four new points of potential failure - for your brakes on the car you drive?
I say four, because now you would have the three joints on the T-connector, plus the sensor itself - as new points of failure; and it doesn't sound like you are even sure it is the vacuum line or pump...
This doesn't sound like the safe thing to do. You don't mention what your problem is exactly (what you are experiencing), but if this was my situation, I would remove the line from the booster, and put a vacuum gauge on it, run the engine to pull the vacuum (via the pump), and see if it compares to what the manual/specs says it should be.
There's probably even a testing procedure outlined in a Haynes/Chilton; likely you run the engine to draw the vacuum, and the shut it down to see if the vacuum holds over time. If it doesn't, then it is the hose or the pump. If it does, then it may be the booster. Depending on the age of the vehicle, you might just want to go ahead and replace all of it.
Its your car, and your risk, of course - but I would definitely think long and hard about messing with the braking system of your vehicle (and potential consequences of doing so)...