According to the long term storage section in the manual, there is nothing wrong to keep it plugged in. Remember the car will wake up to top up the 12V DC once in a while...if it left unplugged long enough that may deplete the HV battery below 30% where it stops maintaining the 12V, which will brick the car at some point then.
That said as most are saying ...for a couple of weeks it does not matter either way especially if it is not too hot (below 90F).