Fix crash when creating thumbnails for 3d textures

[BlueCube3310]

Fixes #97879

Ensures that the depth is equal to the amount of slices.

[clayjohn]

Seems fine. But I wonder why this situation was happening in the OP? Is the editor somehow trying to preview the noise texture before it is created?

[BlueCube3310]

Seems fine. But I wonder why this situation was happening in the OP? Is the editor somehow trying to preview the noise texture before it is created?

I think before actual noise data is provided, the editor creates a dummy texture with uninitialized data that doesn't match up with its properties

[clayjohn]

That makes sense. Thank you.

I think you need to rebase on master to pass CI. There were some changes to the MacOS CI earlier today

[Repiteo]

Thanks!