[OSD Wizards] OSD CCS AWS & Rosa - Create cluster - list regions filtered by AWS credentials

Beni wrote:

UI now relies on data "for everyone" /api/clusters_mgmt/v1/cloud_providers/aws/regions
In CCS mode, it should switch to use personal data
/api/clusters_mgmt/v1/aws_inquiries/regions with CCS credentials.
(We already call getAWSCloudProviderRegions() but currently we only use it for validation, we don't save the response)

• HAC-2170's main goal is filter supported regions by OCP version, and current backend MR will add that ability to aws_inquiries/regions endpoint which covers CCS scenarios.  Some additional API change might be needed to filter by version in non-CCS case, discussing on SDA-6667...
• Showing opted-in regions is separate goal, only relevant for CCS.  I'm not certain if that should use aws_inquiries/regions or cloud_providers/aws/available_regions API or both.  I think we want separate ticket to track it, even if the implementation overlaps.

Acceptance Criteria

• For OSD CCS AWS & Rosa wizards
• regions dropdown on Cluster details step should be filtered by AWS credentials
• If user changers credentials, UI must invalidate the regions response to trigger refetch with new credentials.