Fix GC logic deleting downloaded files instead of only temp directories

What does this MR do and why?

• Garbage collector intended to clean up temporary files when downloading directories was inadvertently catching singular files when they were downloaded. This fixes the logical issues responsible for that.
• Resolves #593 (closed)

How to set up and validate locally

• Download a singular file from Crafty's file manager.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• Have you checked this doesn't interfere/conflict/duplicate someone elses work?
• Have you fully tested your changes?
• Have you resolved any lint issues?
• Have you assigned a reviewer?
• Have you applied correct labels?