`TabItem` enters dragging state in `TabView` with `CanReorderTabs=false`

### Describe the bug

When `TabView` does not allow dragging & reordering of tabs, items can still enter dragging visual state and will stay in it until unfocused and refocused.

### Why is this important?

Invalid visual state.

### Steps to reproduce the bug

1. Use the following XAML:

```xml

A
B

```

2. Try to drag one of the items
3. **Note the item enters dragging visual state `DragDropVisualVisible` and stays in it**

https://github.com/user-attachments/assets/e04ecc1b-584b-49fc-8588-04691cc657c7

### Actual behavior

_No response_

### Expected behavior

_No response_

### Screenshots

_No response_

### NuGet package version

None

### Windows version

_No response_

### Additional context

_No response_

Start by tracing the TabView and TabItem drag-and-drop visual-state handling, reproducing the XAML case with CanReorderTabs="False". The work is done when attempting to drag a tab no longer leaves it in the DragDropVisualVisible state, with coverage for this configuration if the existing tests provide a suitable entry point.

Written by the indexing model from the issue text.