Issue 2241 and 2243 - reinstate individual reveal test and disable only the broken step

Reinstated the test for individual reveals in challenges (based on Purim gifts) which was enabled by the resolution to Issue 2241. However, there is still a deferred step - sending emails - as that is waiting on the resolution to Issue 2243 (and sorry, I couldn't work out a fix this time around). Still, this will tell us if the actual revealing process ever breaks.

The origin of the test: https://code.google.com/p/otwarchive/issues/detail?id=2241
The issue that is deferred: https://code.google.com/p/otwarchive/issues/detail?id=2243