Currently, the GitHub actions test-and-demo workflow, utilizes artifact caching to cache build assets and speed up the build process. However, there seems to be an issue with generating the cache key, since it always evaluates to "Linux-".

This problem results in us never really caching the actual build artifacts, and potentially slowing CI down.

Acceptance Criteria:

• Cache key is calculated correctly so that build artifacts are cached
• Built assets are restored in each step where necessary