autopkgtest should not fail if /builds/username/pkgname/debian/output/debci/binaries doesn't exist

Some recent output of a debci autopkgtest log:

autopkgtest [00:50:22]: test general: -----------------------]
autopkgtest [00:50:22]: test general:  - - - - - - - - - - results - - - - - - - - - -
general              PASS
autopkgtest [00:50:22]: @@@@@@@@@@@@@@@@@@@@ summary
general              PASS
I: test artifacts available at /builds/josch/debian-installer/debian/output/debci
[32;1m$ rm -r ${WORKING_DIR}/debci/binaries[0;m
rm: cannot remove '/builds/josch/debian-installer/debian/output/debci/binaries': No such file or directory
section_end:1584233425:build_script
[0Ksection_start:1584233425:after_script
[0Ksection_end:1584233426:after_script
[0Ksection_start:1584233426:upload_artifacts_on_failure
[0K[32;1mUploading artifacts...[0;m
/builds/josch/debian-installer/debian/output/debci: found 10 matching files[0;m 
Uploading artifacts to coordinator... ok          [0;m  id[0;m=611319 responseStatus[0;m=201 Created token[0;m=CJaiEy3j
section_end:1584233430:upload_artifacts_on_failure
[0K[31;1mERROR: Job failed: exit code 1
[0;m

The autopkgtest passed but overall this was still a failure because it could not remove that directory.

Please make it such that the non-existance of that directory is not an autopkgtest failure.