design: Move chatbackup in adaptive bottom sheet

lib/pages/bootstrap/bootstrap_dialog.dart

@@ -13,6 +13,7 @@ import 'package:share_plus/share_plus.dart';
 import 'package:fluffychat/config/themes.dart';
 import 'package:fluffychat/utils/platform_infos.dart';
 import 'package:fluffychat/widgets/adaptive_flat_button.dart';
+import '../../utils/adaptive_bottom_sheet.dart';
 import '../key_verification/key_verification_dialog.dart';
 
 class BootstrapDialog extends StatefulWidget {
@@ -24,18 +25,10 @@ class BootstrapDialog extends StatefulWidget {
     required this.client,
   }) : super(key: key);
 
-  Future<bool?> show(BuildContext context) => PlatformInfos.isCupertinoStyle
+  Future<bool?> show(BuildContext context) => showAdaptiveBottomSheet(
-      ? showCupertinoDialog(
         context: context,
         builder: (context) => this,
-          barrierDismissible: true,
+        maxHeight: 600,
-          useRootNavigator: false,
-        )
-      : showDialog(
-          context: context,
-          builder: (context) => this,
-          barrierDismissible: true,
-          useRootNavigator: false,
       );
 
   @override

lib/utils/adaptive_bottom_sheet.dart

@@ -9,6 +9,7 @@ Future<T?> showAdaptiveBottomSheet<T>({
   required Widget Function(BuildContext) builder,
   bool isDismissible = true,
   bool isScrollControlled = true,
+  double maxHeight = 480.0,
 }) =>
     showModalBottomSheet(
       context: context,
@@ -16,8 +17,8 @@ Future<T?> showAdaptiveBottomSheet<T>({
       useRootNavigator: !PlatformInfos.isMobile,
       isDismissible: isDismissible,
       isScrollControlled: isScrollControlled,
-      constraints: const BoxConstraints(
+      constraints: BoxConstraints(
-        maxHeight: 480,
+        maxHeight: maxHeight,
         maxWidth: FluffyThemes.columnWidth * 1.5,
       ),
       clipBehavior: Clip.hardEdge,