Tests custom breadcrumbs settings

I will revise it.

I reviewed the tests in drupal 9.5 version

Testing /app/web/modules/contrib/custom_breadcrumbs
...                                                                 3 / 3 (100%)

Time: 01:00.519, Memory: 12.00 MB

OK (3 tests, 53 assertions)

Remaining self deprecation notices (3)

  3x: The Drupal\Tests\custom_breadcrumbs\Functional\CustomBreadcrumbsTest::$modules property must be declared protected. See https://www.drupal.org/node/2909426
    3x in DrupalListener::startTest from Drupal\Tests\Listeners

I also tested in drupal 10.1 version

 Testing /app/modules/contrib/custom_breadcrumbs
...                                                                 3 / 3 (100%)

Time: 00:13.488, Memory: 10.00 MB

OK (3 tests, 53 assertions)

Remaining self deprecation notices (3)

  3x: The Drupal\Tests\custom_breadcrumbs\Functional\CustomBreadcrumbsTest::$modules property must be declared protected. See https://www.drupal.org/node/2909426
    3x in DrupalListener::startTest from Drupal\Tests\Listeners

I applied patch cleanly
All the tests passed.
Module isn't breaking
Changes are following drupal coding standards
Tests logic is also good.
Moving to RTBC.

@Krzysztof Domański 📌 Invalidate Breadcrumbs cache after saving Custom Breadcrumbs Settings Fixed merged, as I can see it is the same patch. I extended it to coverage also breadcrumb title trim functionality.

Looks good!