can't handle null SED

[tpolecat]

@cquiroz is getting Error parsing point profile when setting the sed to null so I think this needs to handle that case:

lucuma-itc/modules/service/src/main/scala/lucuma/itc/service/ItcPartials.scala

Line 455 in 533d0f2

case ("sed", ObjectValue(sed)) ::

[tpolecat]

Or if the ITC can't do anything with the null sed maybe it should be non-nullable in the ITC schema?

[swalker2m]

At some point, it was determined that SED should be optional and we've been suffering fallout from that change. See gemini-hlsw/lucuma-odb#272 for example.

[swalker2m]

I can make it refuse to call the ITC if the SED isn't available, but that code changes a lot in gemini-hlsw/lucuma-odb#268 so I'd prefer to do it there. We should then make it not optional in the ITC schema.