fix "Null check operator used on a null value"

[rounce]

The error may occur after using updateUrlInfo for example.

[codecov[bot]]

Codecov Report

Merging #124 (18148fc) into master (ec5d9b5) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #124   +/-   ##
=======================================
  Coverage   90.74%   90.74%           
=======================================
  Files          25       25           
  Lines        1134     1135    +1     
=======================================
+ Hits         1029     1030    +1     
  Misses        105      105           

Impacted Files	Coverage Δ
lib/src/controllers/match_controller.dart	95.65% <100.00%> (+0.03%)	:arrow_up:
lib/src/routers/router_delegate.dart	85.07% <100.00%> (ø)

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[SchabanBo]

Hi @rounce , Thanks for the PR. could you add test for it or give a code where I can reproduce the error, so I could write test.

[rounce]

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:qlevar_router/qlevar_router.dart';

import 'helpers.dart';
import 'test_widgets/test_widgets.dart';

void main() {
  QR.settings.enableDebugLog = false;
  QR.settings.enableLog = false;
  final pages = [
    QRoute(path: '/', builder: () => const Scaffold(body: WidgetOne())),
    QRoute(
        name: 'two',
        path: '/two/:id',
        builder: () => const Scaffold(body: WidgetTwo())),
    QRoute(
        name: 'three',
        path: '/three',
        builder: () => const Scaffold(body: WidgetThree())),
  ];

  testWidgets('124', (tester) async {
    QR.reset();
    await tester.pumpWidget(AppWrapper(pages));
    await QR.navigator.push('/two/1');
    QR.updateUrlInfo('/two/1/test');
    QR.updateUrlInfo('/two/1');
    await QR.navigator.push('/three');
    await QR.back();
    await QR.back();
    printCurrentHistory();
  });
}