Link field displays duplicate validation errors at fieldset, URI, and title levels

Problem/Motivation

When a Link field is used with the Conditional Fields module and validation fails, the same validation error is displayed multiple times.

The validation error is rendered at three different levels:

Fieldset level — the error is displayed for the Link field container.
URI level — the same error is displayed for the uri element.
Title level — the same error is displayed for the title element.

This results in duplicate and confusing validation messages for the user.

Steps to reproduce

1. Enable the Conditional Fields module.
2. Create a form/content type containing a Link field with optional title field.
3. Make the Link field conditionally required.
4. Leave the Link field empty.
5. Submit the form.
6. Observe the validation errors.