Many tests are at some point dependent on RB.DnDUploader. Some tests

initialize this, some clear it out, and some don't specifically deal

with it but views they set up do. Depending on which subsets of tests

are run, tests may break due to a lack of an available instance for the

uploader, or due to an instance not being cleaned up.
This change fixes up all those tests, ensuring that we always clear it

out in views that implicitly or explicitly deal with it, and create it

if necessary prior to running tests.

All unit tests pass.
Ran subsets of tests that were breaking before when run in isolation,

and saw that they now pass.