[Students in EECS 2021: don't modify the board until we're had a chance to discuss it in class. Let's cross all the T's and dot all the i's before you do this]
To use a PICKit 4 or SNAP programmer with the Grove Beginner Kit for Arduino you need to cut a trace between the USB converter chip and the ATMEGA328P. Here I'll walk you through the process.
A similar cut needs to be done to standard Arduino UNO boards to allow them to be programmed in MPLAB X, too.
Thanks to Mr. Jaspal Singh, Mr. Eric Prandovsky and Mr. Gayan Gamage at York University for their support in the EECS 1011, 1021 and 2021 courses.