fixed issue to where screen reader reads all buttons when opening datepicker (#152705)

removed container=true property from Semantics wrapper of datepicker dialog. This prevents the screen reader from reading every button in the datepicker dialog whenever a user opens it, reducing SR noise.

Before: https://screencast.googleplex.com/cast/Njc0Mzc1MDA5MTk5NzE4NHw2NTU5ODI4YS0xNA
After: https://screencast.googleplex.com/cast/NTYxMDUwOTIxMzYzMDQ2NHxjOWQ2M2YzNy1hYQ

fixes b/345297872

NOTE: Please let me know if a test is needed for this, since it is only deleting code.

packages/flutter/lib/src/material/calendar_date_picker.dart

@@ -435,7 +435,6 @@ class _DatePickerModeToggleButtonState extends State<_DatePickerModeToggleButton
             Flexible(
               child: Semantics(
                 label: MaterialLocalizations.of(context).selectYearSemanticsLabel,
-                excludeSemantics: true,
                 button: true,
                 container: true,
                 child: SizedBox(
@@ -788,6 +787,8 @@ class _MonthPickerState extends State<_MonthPicker> {
     final Color controlColor = Theme.of(context).colorScheme.onSurface.withOpacity(0.60);
 
     return Semantics(
+      container: true,
+      explicitChildNodes: true,
       child: Column(
         children: <Widget>[
           SizedBox(

packages/flutter/test/material/calendar_date_picker_test.dart

@@ -855,8 +855,11 @@ void main() {
 
         // Year mode drop down button.
         expect(tester.getSemantics(find.text('January 2016')), matchesSemantics(
-          label: 'Select year',
+          label: 'Select year\nJanuary 2016',
           isButton: true,
+          hasTapAction: true,
+          hasFocusAction: true,
+          isFocusable: true,
         ));
 
         // Prev/Next month buttons.
@@ -1104,8 +1107,11 @@ void main() {
 
         // Year mode drop down button.
         expect(tester.getSemantics(find.text('January 2016')), matchesSemantics(
-          label: 'Select year',
+          label: 'Select year\nJanuary 2016',
           isButton: true,
+          hasTapAction: true,
+          hasFocusAction: true,
+          isFocusable: true,
         ));
 
         // Year grid only shows 2010 - 2024.

packages/flutter/test/material/date_picker_test.dart

@@ -11,6 +11,7 @@ import 'dart:ui';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import '../widgets/clipboard_utils.dart';
@@ -1682,6 +1683,23 @@ void main() {
       });
       semantics.dispose();
     });
+
+    // Regression test for https://github.com/flutter/flutter/pull/152705
+    testWidgets('datepicker dialog semantics node not focusable', (WidgetTester tester) async {
+      await tester.pumpWidget(MaterialApp(
+        home: Material(
+          child: DatePickerDialog(
+            initialDate: initialDate,
+            firstDate: firstDate,
+            lastDate: lastDate,
+          ),
+        ),
+      ));
+
+      final SemanticsNode node = tester.semantics.find(find.byType(DatePickerDialog));
+      final SemanticsData semanticsData = node.getSemanticsData();
+      expect(semanticsData.hasFlag(SemanticsFlag.isFocusable), false);
+    });
   });
 
   group('Keyboard navigation', () {