[go_router] Don't clear listeners when logging is disabled

[johnpryan]

go_router should not clear listeners on the root logger. See also dart-archive/logging#118

cc: @devoncarew

Fixes flutter/flutter#106653

[chunhtai]

LGTM

[DartAndrik]

You guys are incredible. Thank you. Just one more thing.
Could you add @visibleForTesting for setLogging or make it private and used for GoRouter instantiation only? As setLogging can be called after the GoRouter instance already configured like in the example for this package:

 final _router = GoRouter(
    debugLogDiagnostics: true,
    routes: [
      GoRoute(
        path: '/',
        builder: (context, state) => const Page1Screen(),
      ),
      GoRoute(
        path: '/page2',
        builder: (context, state) => const Page2Screen(),
      ),
    ],
  );

It may be confusing why setLogging(false) didn't do such switching off package logging.

[chunhtai]

LGTM

[auto-submit]

auto label is removed for flutter/packages, pr: 2533, Failed to merge pr#: 2533 with OperationException(linkException: null, graphqlErrors: [GraphQLError(message: Base branch was modified. Review and try the merge again., locations: [ErrorLocation(line: 2, column: 3)], path: [mergePullRequest], extensions: null)]).

[chunhtai]

@johnpryan It looks like there is merge conflict