nvcomp try proprietary binary when 'always_download' is on

[robertmaynard]

Description

The nvcomp package will ignore the downloaded proprietary binary, and build from source when "always_download" : true is in the versions.json file.

This was found when using a pinned override file, as it failed to use the correct nvcomp version.

Merging this unblocks spark-rapids

Checklist

• [x] I am familiar with the Contributing Guidelines.
• [x] New or existing tests cover these changes.