CLC-4064 - Roster Photos Feature doesn't print nicely

https://jira.ets.berkeley.edu/jira/browse/CLC-4064

When there is no picture available, the API shouldn't return any. On the front-end we check for it and if it doesn't exist, we show the no photo available.
@raydavis See the previous comment from @ctweney, actually just followed his suggestion to add it to the query. Also realize that photo_bytes doesn't contain the actual picture data. We just use it to see whether the student has a photo or not.

And yes, it would be good to discuss alternatives next week.