Description of problem:

For a ROSA hypershift cluster, to add a new machine pool (as part of day2) , the private subnet is mandatory requirement. If the private subnet is failed to load due to issues in VPC, then we should never allow "Add machine pool" button from the dialog. Currently button has enabled and this will report error when submitting request to backend.

How reproducible:

always

Steps to Reproduce:

1. Open OCM UI staging.
2. Open an ROSA Hypershift cluster where the machine pool configured VPC is not reachable or having issues.
3. Go to machine pool tab.
4. Click "Add machine pool" button.
5. In "Add machine pool" dialog , fill all required fields.
6. Click "Add machine pool" button.
7. See the behavior.

Actual results:

"Add machine pool" button enabled from "Add machine pool" dialog although required subnet definition failed to load from configured VPC. This is wrong behavior.

Expected results:

"Add machine pool" button should be disabled from "Add machine pool" dialog when subnet definition failed to load from configured VPC.