Avoid checking for null on non-nullable property for projection

[glen-84]

Summary of the changes (Less than 80 chars)

• Check the nullability of properties before doing a null check.

Closes #6604.

---

• I'm not sure what context.InMemory is about.
• Is there an existing utility function/extension method for checking this nullability?
• Should these nullability checks be cached?

[glen-84]

@PascalSenn Is this feasible?

[PascalSenn]

@glen-84

We did remove it once for ef core and then added it again:
#6604 (comment)

So i am not sure what to do now. I believe if you do not do the nullcheck then it will include all the fields from the child or something like this.

[glen-84]

You removed it completely, or conditionally based on the nullability of the property?

Should I be seeing something significant in the test snapshots, or is there no test that would highlight the previous issue? If not, then I think that we need that test to exist in order to have some more confidence here.

[PascalSenn]

This is the context:
28ed6ae

So you only apply it when the property is nullable and ef does not complain?

[glen-84]

So you only apply it when the property is nullable and ef does not complain?

By "does not complain", you mean that the tests in HotChocolate.Data.Projections.SqlServer.Tests pass? If so, yes, they all pass.

[glen-84]

This will quite likely fix these issues as well:

• Projection cause "Index out of range" on Database first EF core (net 6)  #5229
• Owned entity returning null if any property is null in net7 #5542