I hope you will all take my word on this, however, that IS the Vacuum pump for the brake booster (What gives your vehicle powered brakes).
If you want to confirm. With the car in park. Just press the brake pedal in rapid succession 10 or so times, and the vacuum pump kicks in, you will hear the sound. ICE vehicles do not usually use a Vacuum pump, as they use the natural vacuum of the internal combustion engine to power the brake booster. EV's do not have that, thus, need a special vacuum pump for the booster. This is not the Air Shocks. If it is the compressor for the air shocks, then they would be defective and leaking, and once parked, the car would lower to it's lowest possible height on the air shock pouch that was damaged.
The vacuum pump usually cannot be heard while driving due to the road noise covering up the sound. At extremely low speeds or at a stand still, it can be heard, and especially when in a garage where the noise can echo.
Now, just imagine all the noises a ICE car makes if it didn't have the engine to mask the sounds
Cheers!