When using continuous shooting mode with my Canon 6D camera and 24-105mm lens at shutter speeds of 1/400 or faster, is it recommended that Image Stabilization should be turned off or doesn’t it matter?
Yup. Off. I consider stabilization to be for One-Shot situations where the shutter speed might be 1-2 stops below the ideal for the focal length. It's not helping at all at 1/400.
I keep it on almost always on telephotos (100mm+) because it stabilizes the viewfinder. I don't have IS on any shorter lenses but I can't imagine it would make much difference one way or the other at that shutter speed.