Investigate error levels in NSIS

[jaimergp]

Shared by @elovelan in https://github.com/ScoopInstaller/Extras/pull/10457#issuecomment-1425155797

@jaimergp, the NSIS docs indicate that NSIS should be able to return a failure exit code. I'm happy to dig into this more if there's a chance that updating constructor might resolve it. I realize that may be a risky proposition however if any software is relying on it always having a return code of 0, so I'm also happy to continue down the path of your original suggestion.