Description of problem:

Under  Networking > configuration wizard step, The public subnet Ids list is always shows empty although VPCs and public subnets are associated to AWS account for selected region.

Steps to reproduce:

1. Launch OCM UI staging.
2. Open ROSA cluster wizard.
3. Select control plane as "Hosted".
4. Select an AWS account and roles in "Account and roles" step.
5. Proceed to next step and select the region as "us-west-2".
6. Proceed to next step and reach "networking" step. 
7. See the public subnet id dropdown and it's values.

Actual results:
The public subnet Ids list is always shows empty although VPCs and public subnets are associated to AWS account for selected region. The backend call also responded with VPC details associated with the accounts.

Expected results:
The public subnet Ids should list all valid public subnets from VPCs according to the AWS account for selected region in wizard