Number of Views Ascending/Descending throws an error

Problem:

When reordering topics to the Number of Views Ascending, Forums throws an error. 

Steps to Reproduce: 

1. Set up a space with a few topics.
2. Select advanced filters
3. Change the ordering to be by the number of views ascending 
4. Notice that Forums throws an error.
5. Now change the ordering to be by the number of views descending.
6. Notice that Forums throws another error.

Expected Outcome

**The topics should be sorted by the number of Views Ascending/descending.