Blender Git Loki

Fix possible crash displaying asset preview from current file

For some reason the asset preview isn't created or loaded correctly in
some instances. This could be addressed with D9974, but hard to tell
since I only have a failing .blend file, no steps to recreate it from
scratch.

Would crash when opening an Asset Browser, selecting an object asset
(that has an invalid preview stored) and opening the Asset Browser
sidebar, so that the preview is visible there.