Fix picker demo safe area layout (#22244)

diff --git a/examples/flutter_gallery/lib/demo/cupertino/cupertino_picker_demo.dart b/examples/flutter_gallery/lib/demo/cupertino/cupertino_picker_demo.dart
index 7e36064..c435401 100644
--- a/examples/flutter_gallery/lib/demo/cupertino/cupertino_picker_demo.dart
+++ b/examples/flutter_gallery/lib/demo/cupertino/cupertino_picker_demo.dart
@@ -75,6 +75,7 @@
   Widget _buildBottomPicker(Widget picker) {
     return Container(
       height: _kPickerSheetHeight,
+      padding: const EdgeInsets.only(top: 8.0),
       color: CupertinoColors.white,
       child: DefaultTextStyle(
         style: const TextStyle(
@@ -85,6 +86,7 @@
           // Blocks taps from propagating to the modal sheet and popping.
           onTap: () {},
           child: SafeArea(
+            top: false,
             child: picker,
           ),
         ),