private/deposit_checks: Ensure checks is done on filename

If done on the full path, the conditional technically fails the check for the wrong reason. This also adds tests on this case.

This got fixed in staging that way. Icinga check got back to green.

Refs. swh/infra/sysadm-environment#5129 (closed)

enabled an automatic merge when the pipeline for 3417639a succeeds

canceled the automatic merge

Jenkins job DDEP/gitlab-builds #62 succeeded .
See Console Output and Coverage Report for more details.

merged