fix: prepare for will pop deprecation

@@ -46,8 +46,11 @@ class ModalBottomSheet extends StatefulWidget {
     required this.child,
     this.minFlingVelocity = _minFlingVelocity,
     double? closeProgressThreshold,
-    this.willPopThreshold = _willPopThreshold,
-  }) : closeProgressThreshold =
+    @Deprecated('Use preventPopThreshold instead') double? willPopThreshold,
+    double? preventPopThreshold,
+  })  : preventPopThreshold =
+            preventPopThreshold ?? willPopThreshold ?? _willPopThreshold,
+        closeProgressThreshold =
             closeProgressThreshold ?? _closeProgressThreshold;
 
   /// The closeProgressThreshold parameter
@@ -107,9 +110,9 @@ class ModalBottomSheet extends StatefulWidget {
   /// Determines how fast the sheet should be flinged before closing.
   final double minFlingVelocity;
 
-  /// The willPopThreshold parameter
+  /// The preventPopThreshold parameter
   /// Determines how far the sheet should be flinged before closing.
-  final double willPopThreshold;
+  final double preventPopThreshold;
 
   @override
   ModalBottomSheetState createState() => ModalBottomSheetState();

@@ -185,6 +185,7 @@ class ModalSheetRoute<T> extends PageRoute<T> {
     return _animationController!;
   }
 
+  // ignore: deprecated_member_use
   bool get _hasScopedWillPopCallback => hasScopedWillPopCallback;
 
   @override

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// ignore_for_file: deprecated_member_use
+
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';