Actually, when we use a command to spawn a wolf, we can't modify the taming probability of the wolf.

A thing that we can do when we spawn a horse. By using the tag "Temper" we can define the difficulty to tame the mob, which define by the way the number of attemps we need to tame the horse.

But when we add this tag in the wolf spawn command, the game doesn't care about the tag and the taming probability don't change.