Mark fields which are only returned by field mask in API

[benolayinka]

Summary

The ids , created_at, updated_at and deleted_at are always returned by the IS. Everything else needs to be selected.

Why do we need this ?

So people aren't confused when fields aren't returned by API

Can you do this yourself and submit a Pull Request?

Yes

[NicolasMrad]

Is this still relevant or to be done soon since it has been moved for 3 quarters so far

[benolayinka]

This is partially addressed by #475

Actually adding a field mask indicator will require manually updating request metadata which we aren't gonna do right now. Will mark gold plating and remove milestone

#475 (comment)