Delete protest button doesn't work on admin page

[guytepper]

When trying to delete an existing protest, clicking on the delete button pop up an alert that says that the protest have been deleted, but it does not.

[guytepper]

It happens because it doesn't really delete the protest, but sets an archived property on it, which we don't condition when we retrieve protests.
We should run a migration to add an archived property on each document (so it'd be easier to query).