Duplicate policy creation with same name returns success in UI

### What happened

When creating a policy/sub-policy, if name is already used, still we get success response in UI.

### Version/commit

_No response_

### Affected browser(s)

_No response_

### Relevant logs/errors

```shell

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### Anything else

_No response_

### Screenshots

_No response_

### Checklist

- [x] I’ve reviewed and agree to follow the code of conduct