Description of problem:

In ROSA Hypershift wizard flow, Initially user has chosen a VPC from machine pool step then went back to previous step and changed the region value. After reaching again to the machine pool step, it was seen that previous VPC selection is shown but disabled until new VPC list loading. User also allowed to proceed to next step with this wrong definitions.This is bad user experience.
See attached recordings VPCHAndlingDefinition.mp4

How reproducible:

always

Steps to Reproduce:

1. Open OCM UI staging.
2. Open Rosa wizard, Choose control plane type as "Hosted".
3. Go to Cluster details step, choose a region along with other required fields.
4. Click "Next" button.
5. Select a VPC and add machine pools by selecting private subnets.
6. Click "Back" button
7. Choose another region value.
8. Click "Next" button.
9. See the behavior of VPC field.

Actual results:

At Step 9, Previously selected VPC (from different region)  shown as selected but disabled until new VPC list loading. User also allowed to proceed to next step with this wrong definitions. This is bad user experience.

Expected results:

At Step 9, All previous selected VPC should be cleared and should show a loading indication until the VPC list is retrieved from back-end