SearchAnchor keyboard covers suggestions when isFullScreen is false

### Steps to reproduce

Write a simple SearchAnchor widget with multiple suggestions and isFullScreen = false

### Expected results

The dialog height should be limited to the size of the screen - keyboard height

### Actual results

It seems like the keyboard opens slightly after the dialog so the bottom padding is not correct.

### Code sample

Code sample

```dart
return SearchAnchor.bar(
isFullScreen: false,
suggestionsBuilder: (context, controller) {
return List.generate(100, (index) => ListTile(title: Text("$index")));
},
);
```

### Screenshots or Video

Screenshots / Video demonstration

https://github.com/user-attachments/assets/13b64fcf-b583-4197-964a-44929fd84a80

### Logs

Logs

```console
[Paste your logs here]
```

### Flutter Doctor output

Doctor output

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```