HOTFIX: Fix the qc.yml to not run mirrors

[matentzn]

This is necessary to be pushed as a hotfix quickly, as some QC pipelines can run mirrors without failing.

I didnt notice this because of chicken egg - I couldnt test qc.yml directly, and it failed because it was not able to find the v1.5 ODK release..

[gouttegd]

No objection to the fix. But I am not sure I understand why this is necessary.

Making the mirror-downloading rules independent of IMP was done to allow custom workflows to depend on a mirror independently of the import pipeline.

But as far as I know, in the standard workflows, the mirrors are only used to refresh the imports, so if we run with IMP=false, no refresh of the imports should be attempted and therefore no mirror-downloading rule should be invoked.

[matentzn]

Maybe the pipelines that failed because of this failed because of custom goals.

This seems to have been the case with OBA: https://github.com/obophenotype/bio-attribute-ontology/actions/runs/8125158836/job/22207444205

But with MAXO it seems to me that mirror/merged.owl was being created for some reason during the QC. this i perhaps because mirror-% is PHONY and therefore executed no matter what?