fix: Incompatible with Flutter 3.32.0

[Conrad598]

Description

It looks like Flutter 3.32.0 changed the signature of Navigator.removeRouteBelow which is causing compilation failed when running tests after upgrading to Flutter 3.32.0. See Flutter#157725.

Steps To Reproduce

1. Install Flutter 3.32.0
2. Create a test that includes import 'package:mockingjay/mockingjay.dart';
3. Execute the test.

Expected Behavior

The test should compile successfully.

Additional Context

mockingjay: 1.0.0
Flutter: 3.32.0

Error: Declared type variables of '_MockNavigatorState.removeRouteBelow' doesn't match those on overridden method 'NavigatorState.removeRouteBelow'.
  void removeRouteBelow(Route<dynamic> anchorRoute) {
       ^
../../../../flutter/packages/flutter/lib/src/widgets/navigator.dart:5656:8: Context: This is the overridden method ('removeRouteBelow').
  void removeRouteBelow<T extends Object?>(Route<T> anchorRoute, [T? result]) {
       ^
../../../../AppData/Local/Pub/Cache/hosted/pub.dev/mockingjay-1.0.0/lib/src/mock_navigator.dart:322:8: Error: The method '_MockNavigatorState.removeRouteBelow' has fewer positional arguments than those of overridden method 'NavigatorState.removeRouteBelow'.
  void removeRouteBelow(Route<dynamic> anchorRoute) {
       ^
../../../../flutter/packages/flutter/lib/src/widgets/navigator.dart:5656:8: Context: This is the overridden method ('removeRouteBelow').
  void removeRouteBelow<T extends Object?>(Route<T> anchorRoute, [T? result]) {
       ^
.

[alestiago]

Assigning @marcossevilla , he will be in charge of ensuring #97 lands and any addition efforts solving this might intake.