Fix _RenderValueIndicator leak (flutter#147451)

Author: Dimilkalathiya

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

@@ -1868,7 +1868,7 @@ class _RenderValueIndicator extends RenderBox with RelayoutWhenSystemFontsChange
       curve: Curves.fastOutSlowIn,
     );
   }
-  late Animation<double> _valueIndicatorAnimation;
+  late CurvedAnimation _valueIndicatorAnimation;
   _SliderState _state;
 
   @override
@@ -1897,6 +1897,12 @@ class _RenderValueIndicator extends RenderBox with RelayoutWhenSystemFontsChange
   Size computeDryLayout(BoxConstraints constraints) {
     return constraints.smallest;
   }
+
+  @override
+  void dispose() {
+    _valueIndicatorAnimation.dispose();
+    super.dispose();
+  }
 }
 
 class _SliderDefaultsM2 extends SliderThemeData {

packages/flutter/test/material/slider_test.dart

@@ -13,6 +13,7 @@ import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/src/physics/utils.dart' show nearEqual;
 import 'package:flutter_test/flutter_test.dart';
+import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
 
 import '../widgets/semantics_tester.dart';
 
@@ -140,7 +141,10 @@ void main() {
     expect(log[0], const Offset(212.0, 300.0));
   });
 
-  testWidgets('Slider can move when tapped (LTR)', (WidgetTester tester) async {
+  testWidgets(
+    // TODO(polina-c): remove when fixed https://github.com/flutter/flutter/issues/145600 [leak-tracking-opt-in]
+    experimentalLeakTesting: LeakTesting.settings.withTracked(classes: <String>['CurvedAnimation']),
+    'Slider can move when tapped (LTR)', (WidgetTester tester) async {
     final Key sliderKey = UniqueKey();
     double value = 0.0;
     double? startValue;