When users provide invalid certificate credentials during creation, the form displays validation errors as expected. When the user clicks Add, the credentials are not stored, but the issue is that no error message is shown to the user to indicate the failure.

Steps to Reproduce:

1. Go to New Item and create an item named Test-Add-Certificate
2. Under Source Code Management, select Git
3. Click on the Add button for credentials
4. In the credentials popup:
5. Select Jenkins as the provider
     Choose Global Credentials (Unrestricted) for the Domain
     Select "Certificate" as the Kind
     Choose "PEM encoded certificate and key" for the Certificate type
6. Leave the Certificate and Private Key fields empty or input invalid data
7. Observe that the form shows validation errors, but after clicking Add, no error message is displayed, and the credentials are not created

Expected Behavior:

If the certificate credentials creation fails, the plugin should display a error message to the user, otherwise its not clear that if the credentials are created.

Actual Behavior:

No error message is displayed, and the credentials are silently rejected.