minifying should also work when no files to minify where found

It is worth mentioning that the minify/concentrate may not find all of the dependencies' javascript files.
This depends on the dependencies' configurations.

I think this is reasonable because, unlike npm packages, bower packages sometimes contain non-javascript parts like images, html, etc...
If there are relative dependencies between those parts, minifying/concentrating only the javascript parts may be a bad idea.

In order to upload the bower dependencies as-is, just add the "components" directory to the kanso.json attachments.