Fix memory leak in BottomNavigationBar (flutter#146748)

Author: ValentinVignal

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

@@ -883,6 +883,9 @@ class _BottomNavigationBarState extends State<BottomNavigationBar> with TickerPr
     for (final _Circle circle in _circles) {
       circle.dispose();
     }
+    for (final CurvedAnimation animation in _animations) {
+      animation.dispose();
+    }
     super.dispose();
   }
 

packages/flutter/test/material/bottom_sheet_test.dart

@@ -7,6 +7,7 @@ import 'dart:ui';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
 
 import '../widgets/semantics_tester.dart';
 
@@ -1282,7 +1283,10 @@ void main() {
     await checkDragHandleAndColors();
   });
 
-  testWidgets('showModalBottomSheet does not use root Navigator by default', (WidgetTester tester) async {
+  testWidgets('showModalBottomSheet does not use root Navigator by default',
+  // TODO(polina-c): remove when fixed https://github.com/flutter/flutter/issues/145600 [leak-tracking-opt-in]
+  experimentalLeakTesting: LeakTesting.settings.withTracked(classes: const <String>['CurvedAnimation']),
+  (WidgetTester tester) async {
     await tester.pumpWidget(MaterialApp(
       home: Scaffold(
         body: Navigator(onGenerateRoute: (RouteSettings settings) => MaterialPageRoute<void>(builder: (_) {