[Stitching] Add MP’s Artist type to Convection’s Submission type.
[Stitching] Add MP’s Artist type to Convection’s Submission type.

mzikherman/metaphysics-1,craigspaeth/metaphysics,mzikherman/metaphysics-1,artsy/metaphysics,artsy/metaphysics,mzikherman/metaphysics-1,artsy/metaphysics,mzikherman/metaphysics-1,craigspaeth/metaphysics