rhel6 MR trying to submit i386 build

Unexpected error after validation: KeyError('i386') in datawarehouse/models/kcidb_models.py in create_from_json at line 651

            arch = pipeline_models.ArchitectureEnum[arch_name] if (arch_name := data.get("architecture")) else None

relates to https://datawarehouse.cki-project.org/kcidb/checkouts/redhat:2085567616

Jira: CKI-6954