Leapp on Red Hat Satellite Capsule 6 fails due to enabling HA or other repos due to older python3- packages on the system

Issue

When updating Red Hat Satellite Capsule from RHEL 7 to RHEL 8 the Capsule receives this error:

leapp.workflow.TargetTransactionCheck.dnf_transaction_check: Errors during downloading metadata for repository 'rhel-8-for-x86_64-highavailability-rpms':
leapp.workflow.TargetTransactionCheck.dnf_transaction_check:   - Status code: 404 for https://satellite.example.com/pulp/repos/organization/environment/content/dist/rhel8/8.6/x86_64/highavailability/os/repodata/repomd.xml (IP: xx.xx.xx.xx)
leapp.workflow.TargetTransactionCheck.dnf_transaction_check: Error: Failed to download metadata for repo 'rhel-8-for-x86_64-highavailability-rpms': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried