OCPBUGS-62085: Update the RHCOS 4.21 bootimage metadata

The changes done here will update the RHCOS 4.21 bootimage metadata and
address the following issues:

COS-3042: GA ROSA-HCP support Windows LI for CNV

This change was generated using:

```
plume cosa2stream --target data/data/coreos/rhcos.json \
    --distro rhcos --no-signatures --name rhel-9.6 \
    --url https://rhcos.mirror.openshift.com/art/storage/prod/streams \
    x86_64=9.6.20251015-1        \
    aarch64=9.6.20251015-1       \
    s390x=9.6.20251015-1         \
    ppc64le=9.6.20251015-1
```

Author: marmijo