File name generation fix

[i-walker]

a mistake from #2678
files before #2678 MyGenerated.kt after org.example.MyGenerated.kt

[nomisRev]

Actually, I think in the kapt version we used org.example.MyGenerated.kt for the file names but not 100% sure.
Otherwise, you can have conflicts between two models with the same name.
For example, io.github.persistence.dto.User and io.github.model.User.

Changing the name of the file like this doesn't impact/break anything, right? @i-walker
If not I think we should leave your change, using FQN is safer than simpleName.

[nomisRev]

Discussed in person. Misunderstood the fix, and this should be merged 👍