Unlink button remains visible and enabled on Change link screen after child feature has already been unlinked from parent

Description

After unlinking a child feature from its parent in a 1-N relation and saving, reopening the child feature and navigating to the Change link screen still shows the "Unlink" button as visible and enabled. The button should not be available when the child has no parent to unlink from.

Environment
[x] Staging [x] PROD

Application (+ app version, build, operating system)

• iOS app: 2026.2.0, iOS 26.0

Steps to reproduce

1. Clone project tester-ws-1/test_relations
2. Open the cloned project in the mobile app
3. Open a child feature that is linked to a parent
4. In edit mode, tap Unlink icon → tap Unlink feature to confirm → save
5. Reopen the same child feature → tap Edit → tap Unlink icon
6. Observe the Change link screen

Actual results
The "Unlink feature" button is visible and enabled on the Change link screen, even though the child feature is no longer linked to any parent.

Expected results
The "Unlink feature" button should not be visible or should be disabled on the Change link screen when the child feature has no parent linked.

Screenshots or logs

https://github.com/user-attachments/assets/ac884c64-d573-4e20-9472-e46c22c26591

Conclusion
Created by Claude and supervised by a human test analyst.

Reproduce the issue in the iOS app using the listed project and steps, then locate the implementation of the Change link screen and its Unlink feature control. Confirm that after unlinking and saving, reopening the child feature hides or disables the control when no parent is linked.