Description of problem:
Subnet name search seems not effective and filtered result as expected from a ROSA Hypershift cluster wizard > Under machine pool step or In "Add machine pool" dialog for an existing cluster.

Ex: Inline are subnet names available under private subnet for machine pool.

jul10jayaHCP-Donotuseforanyothertestings-subnet-private3-us-west-2c
jul10jayaHCP-Donotuseforanyothertestings-subnet-private6-us-west-2c
jul10jayaHCP-Donotuseforanyothertestings-subnet-private5-us-west-2b
jul10jayaHCP-Donotuseforanyothertestings-subnet-private2-us-west-2b
jul10jayaHCP-Donotuseforanyothertestings-subnet-private1-us-west-2a
jul10jayaHCP-Donotuseforanyothertestings-subnet-private4-us-west-2a

If user search with subnet name "us-west-2a" 

It matches with multiple subnet names wrongly as above and filtered. The expectation is that, it should list only subnet names that matches with "us-west-2a" substring from the names. Similar issue with other substring "private1" search value.
It works well when user searches with "2a" string.

See recordings attached SearchSubnetNames.mp4

Steps to reproduce:

1. Launch OCM UI staging
2. Open ROSA Hypershift wizard.
3. Reach to machine pool step after filling required values in each step.
4. Select VPC (in this case, 
5. Under machine pool > private subnet names drop-down, Keep "us-west-2a" string or similar substring in "Filter by subnet name"
6. View the value filter behavior.
7. Repeat the step 5, with search value "private1" or similar substring.
8. View the value filter behavior.

Actual results:

Subnet name filter behavior seen in step 5 seems not accurate and not as expected.
In above case, multiple subnet names wrongly filtered although searched string doesn't match accurately with filtered result.

Expected results:

Subnet name filter behavior should be,  match with searched string and see if there is possible substring in that and filter results accordingly.