I don't think there is a setting to turn off interactive sort, but there is a bit of a trick you can apply. If you use any of the inter-row functions -- such as Above(), interactive sorting in a table is disabled. So wrap one of your measures in Above() with an offset of 0. For example, assume your Measure is "sum(Sales)". Change this to:
You will get the same results but interactive sort will be disabled. This will mess with the total values though so you may have to change the total mode to Sum.