Handle errors in updateTranslation

[WULCAN]

Description

The server action updateTranslation returns an explicit object for some errors but throws a MessageNotFound if the request is for an unrecognized message.

I don't know exactly what happens with thrown errors from server actions but if we chose explicit error-representing objects for the other cases, I suspect our client will not handle this thrown error very well.

1. Understand and describe how thrown errors are handled in server actions.
2. Review how that affects our use of updateTranslation
3. Potentially update our error handling in updateTranslation

Estimated size (S, M, L)

I think this issue is Small because the problem is local and contained.

Possible implementations

One possibility is to return an explicit error-representing object instead. Our client-side code probably handles those.

Open questions

1. In what cases can this error state actually happen?
2. What is the ideal error handling for those cases?