Description of problem:

While adding the machine pool using "Add machine pool" option from machine pool tab, The private subnet id field takes longer times to load i.e approximately 25s to 30s . It will be keep showing the status as "Loading subnets ..." and user has to wait for the same. This is not really user friendly when user wants to add more machine pool set to cluster. This need to be optimized.

Steps to reproduce:

1. Install ROSA hypershift cluster via CLI .
2. Launch OCM UI staging.
3. Once installation is successful, Open the newly installed ROSA hypershift cluster.
4. Navigate to machine pools tab and click on the "Add machine pool" button.
5. View the behavior of private subnet id field.
6. Repeat Step 4 action multiple times.

Actual results:
The private subnet id field takes longer times to load i.e approximately 25s to 30s .
It will be keep showing the status as "Loading subnets ..."

Expected results:
The private subnet id field should not take longer times to load every time when user clicks on the "Add machine pool" option to add machine pools for cluster. We need to optimize loading time.