"Change" button in the "No model selected" warning stays enabled without an AI subscription and opens an empty "Select AI Model" window that offers no models and no explanation

Steps to reproduce:

1. Sign in to an account with no active Unity AI subscription
2. Create a new project 
3. From the toolbar, select AI > Generate New > 3D Object
4. Select it and double-click
5. In the "New Mesh" window, observe the "No model selected - Please select a model" warning and the state of the "Change" button next to it
6. Hover the "Change" button and read the tooltip
7. Click it
8. Observe the result

Actual results: The "Change" button is rendered enabled, and clicking it opens the "Select AI Model" window with no models in it - the content area reads only "No models available". The window offers a Search field, Sort options (Recently Used / Alphabetical / Reverse Alphabetical), and a Favorites checkbox, none of which can return a result. Nothing in the window explains that the empty list is caused by the missing subscription, so the user reaches a dead end with no route forward

Expected results: Buttons should be disabled

Reproducible with versions: 2.17.0-pre.1 (6000.0.80f1, 6000.6.0b8), 2.18.0-pre.2 (6000.3.23f1, 6000.5.7f1, 6000.7.0a5)

Tested on (OS): MacBook Pro - Tahoe 26.6.1