Remove redundant check
In around 2/3rd of the cases, we don't check that currentIndex of tabs is less than the number of tabs, because it is not needed. It is also not needed in the other cases, so remove that.
In around 2/3rd of the cases, we don't check that currentIndex of tabs is less than the number of tabs, because it is not needed. It is also not needed in the other cases, so remove that.