message: fixes bug in probing that happened after merge
diff: @@ -165,9 +165,10 @@ def key_pressed(key):
  robot.reset()
  pipette = instruments.Pipette(mount='right', channels=1)
  - probe_center = tuple(probe_instrument(pipette, robot))
  + px, py, pz = tuple(probe_instrument(pipette, robot))
  + pz -= TIP_LENGTH
  robot.config = robot.config._replace(
  - probe_center=probe_center
  + probe_center=(px, py, pz)
  )
  status('Tip probe')
  # save calibration point and move to next
  