Build: Copy-Dist - Investigate if missing files will make CI fail

[pano9000]

Describe Task

We had some issues in the latest nightly release action, caused by some files that were moved/deleted.
e.g.
Error during copy: Error: ENOENT: no such file or directory, lstat 'node_modules/react/umd/react.production.min.js'

https://github.com/TriliumNext/Notes/actions/runs/13802628088/job/38607679715#step:6:2700

However CI did NOT fail, but happily continued -> this shouldn't be happening IMHO.

Let's investigate why it did NOT fail :-)