I have been wondering about this question for awhile now. How witchbolt is written, If any teleport like effect (misty step, thunder step, dimension door etc.) Be it the caster of witchbolt or  the target of the witchbolt.  Cast a teleportation like spell end the witchbolt effects. Seeing the line connecting the two is momentarily broken.

I personally think it would, but I would like to see what other people think.

Teleportation doesn't provide so it wouldn't end the spell that way.

Additionally, teleportation is instantaneous so as long as they're teleporting from a point within the spells range to another point within the spells range, it wouldn't end either. There's no intervening point where they're 'somewhere else' that isn't in the spells range.

Not broken by the teleport, but  With bolt says "The spell also ends if the target is ever outside the spell's range or if it has total cover from you."

Most likely if they are Misty Stepping, they end up outside the Spell's range of 30 ft.