Not exactly, Knime does not try every possible combination. When it has selected the first feature, it leaves that feature in place for the rest of the process, then it selects the second feature, and so on. So instead of 10!, the number of combinations Knime tries is 10+9+8+…=10*(10+1)/2. But I think forward feature selection is mostly used when one wants a model with relatively few features, so the process is stopped at, for example, 4 features. Then Knime will try 10+9+8+7 models.
If you want to do an exhaustive search of all possible combinations, you can use an R snippet and the regsubsets function from the “leaps” library in R.