ci: Stop pulling assets cache in compile-assets jobs

What does this MR do and why?

Now that the new "cache compile assets as package" strategy has proven to work well, we can stop pulling the native cache.

This has two benefits:

• no cache download means faster job
• it reduces the change of conflicting assets, such as gitlab-org/quality/engineering-productivity/team#101 (comment 1168355116)

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.