Fix crash when duplicating Decal or Light3D nodes

[Namey5]

Crash was caused by duplicating Node properties generically with no textures assigned to the Decal triggering a null-deref in some validation code.

Change in code style was by clang-format.

Fixes #100629

[akien-mga]

I fixed up the clang-format issue to respect the original intent :)

clang-format just needs knowing how to talk to it :P

[akien-mga]

I amended @jaydensipe's #100639 in this commit as the two changes are related, so it makes sense to merge them together as a single commit. And so I added @jaydensipe as co-author here.

[akien-mga]

Thanks @Namey5 and @jaydensipe!