Steps to Reproduce

1. Create an HCP cluster or use an existing one.
2. In the cluster details page, navigate to the Access Control tab.
3. Create an htpasswd identity password identity provider and add multiple users to it while creating the idp.
4. Once the htpasswd idp is created, create another htpasswd identity provider and add multiple users with the same username list entered previously.

Expected Result

The system should show an error stating that the
"This username is already taken, or the username should not duplicate"

Actual Result

The system does not throw any error and accepts the same user input multiple times.