Fix and reenable context_menus email button test (#1585)

experimental/context_menus/test/email_button_page_test.dart

@@ -10,8 +10,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'utils.dart';
 
 void main() {
-  testWidgets(
-    'Selecting the email address shows a custom button',
+  testWidgets('Selecting the email address shows a custom button',
       (tester) async {
     await tester.pumpWidget(const MyApp());
 
@@ -19,8 +18,9 @@ void main() {
     await tester.dragUntilVisible(
       find.text(EmailButtonPage.title),
       find.byType(ListView),
-        const Offset(0.0, -200.0),
+      const Offset(0.0, -100.0),
     );
+    await tester.pumpAndSettle();
     await tester.tap(find.text(EmailButtonPage.title));
     await tester.pumpAndSettle();
 
@@ -49,8 +49,8 @@ void main() {
     expect(find.text('Send email'), findsNothing);
     switch (defaultTargetPlatform) {
       case TargetPlatform.iOS:
-          expect(find.byType(CupertinoTextSelectionToolbarButton),
-              findsNWidgets(2));
+        expect(
+            find.byType(CupertinoTextSelectionToolbarButton), findsNWidgets(2));
         break;
       case TargetPlatform.macOS:
         expect(find.byType(CupertinoDesktopTextSelectionToolbarButton),
@@ -97,8 +97,8 @@ void main() {
     expect(find.text('Send email'), findsOneWidget);
     switch (defaultTargetPlatform) {
       case TargetPlatform.iOS:
-          expect(find.byType(CupertinoTextSelectionToolbarButton),
-              findsNWidgets(3));
+        expect(
+            find.byType(CupertinoTextSelectionToolbarButton), findsNWidgets(3));
         break;
       case TargetPlatform.macOS:
         expect(find.byType(CupertinoDesktopTextSelectionToolbarButton),
@@ -114,7 +114,5 @@ void main() {
             find.byType(DesktopTextSelectionToolbarButton), findsNWidgets(4));
         break;
     }
-    },
-    skip: true, // TODO(justinmc): Make this test pass and re-enable.
-  );
+  });
 }