Figure out `GB` vs `GiB` inconsistencies for vSphere provider

EKS-A currently accepts the disk size in GiB as passes it to CAPV which also expects disk size in GiB.
But the vSphere UI shows the same disk size value but with GB suffix.

For example, if you set `diskGiB` to 22 in EKS-A, the vSphere UI shows the disk size as `22 GB` not `22 GiB`.
Getting the disk size using govc also returns the values in KB.
```bash
$ govc device.info -vm bottlerocket-kube-v1-24 -json | grep CapacityInKB
"CapacityInKB": 23068672,
```
which when converted in GB also shows 22. (`23068672 KB / 1024 / 1024 = 22 GB`)

Start by tracing how EKS-A's diskGiB value is passed to CAPV and represented in the vSphere UI, then compare those results with the govc CapacityInKB output shown in the issue. Done means determining whether the values or labels are inconsistent and documenting the required correction.

Written by the indexing model from the issue text.