Description:

When user switches the control plane from "hosted" to "standalone" from Wizard flow, under the network step > Virtual Private Cloud (VPC) > "Install into an existing VPC" checkbox is disabled and "Configure a cluster-wide proxy" is enabled. This is wrong behavior and ideally both checkboxes  "install into an existing VPC checkbox" and "Configure a cluster-wide proxy" should be enabled.
 
How reproducible:

 Always

Steps to Reproduce:

1. Launch OCM staging.
2. Open ROSA wizard , Select Control plane as "Hosted" from control plane step.
3. Proceed with next steps and under networking step,
4. Choose Cluster privacy as "Public".
5. Select the checkbox "Configure a cluster-wide proxy".
6. Go back to "Control plane" step.
7. Choose the type as "Standalone"
8. Proceed with next steps and reach to "networking" step
9. View the behavior of widgets under "Virtual Private Cloud (VPC)"

Actual results:
In Step 9 ,"Install into an existing VPC" checkbox is unchecked and disabled although "Configure a cluster-wide proxy" checkbox is enabled in wizard. This is wrong in ROSA classic wizard flow as cluster-wide proxy could only support when user uses existing custom VPC.

Expected results:

In Step 9, Both "Install into an existing VPC" and  "Configure a cluster-wide proxy" check boxes should be enabled and unchecked from the UI, so that it avoid confusions and user allowed to make their choices.