codeintel: Remove upload files after processing

Created by: efritz

Ensure that upload files are removed after successful processing (when a new db is posted to the bundle manager) and after unsuccessful processing without retries (when the upload record is marked as errored). This will stop spurious alerts from the bundle manager janitor from occurring.

This doesn't affect correctness, as the files are eventually deleted by the janitor today. This just increases the efficiency of the janitor process and will keep the disks size below a cleanup threshold for longer.

Closes https://github.com/sourcegraph/sourcegraph/issues/10358.