When multiple relations share the same phone number or email address, don't automatically link to the most recently used relation: show all matching relations so the user can choose.

Current behaviour: when a phone number or email address matches multiple relations, the item is automatically linked to the most recently used relation.

Expected behaviour: present all matching relations and let the user select the correct one.

Why: auto-linking to the most recently used relation silently attaches items to the wrong one, which is easy to miss and awkward to correct afterwards.