Thats a good question
I have never used a pico for a speed control before and the servos I have used did not have that resistor. I would just take note of where it is connected to the board, then try the micro adjustable per instructions above. Substitute a wire for the hard resistor. If it does not work, put the hard resistor back in.
I dunno..... Let me know what happens. It should not harm the board either way. Just be careful soldering......