Make uri required on the front-end when title filled-in

Problem/Motivation

The uri of the link field is not marked as required (by asterisk) in the front-end, when the title of the link field is inserted.

This is similar to what has been done in #2613924: Link text isn't marked as required about the link text.

Steps to reproduce

• Use a link field that is not required
• Make link title optional or required
• Enter text in link title.
• The link uri is not getting marked required, although it is required now.

Proposed resolution

Use Drupal #states to mark the uri in the frontend as required as soon a something is entered in link title.

Remaining tasks

Provide a patch

User interface changes

Asterisk is shown on uri part of link field if the conditions described above are met

API changes

none

Data model changes

none

Release notes snippet

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