Branch Test Failure on PHP 8.1

Problem/Motivation

Tests pass with PHP 8.0, but with PHP 8.1, I'm seeing an unexpected failure:

Drupal\Tests\twig_ui\FunctionalJavascript\TemplateFormTest

fail: [Other] Line 0 of sites/default/files/simpletest/phpunit-1.xml:
PHPUnit Test failed to complete; Error: PHPUnit 9.5.20 �[44m#StandWith�[0m�[43mUkraine�[0m

Warning:       Your XML configuration validates against a deprecated schema.
Suggestion:    Migrate your XML configuration using "--migrate-configuration"!

Testing Drupal\Tests\twig_ui\FunctionalJavascript\TemplateFormTest
F.                                                                  2 / 2 (100%)

Time: 00:14.126, Memory: 4.00 MB

There was 1 failure:

1) Drupal\Tests\twig_ui\FunctionalJavascript\TemplateFormTest::testTemplateFormTemplateLoad
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
  * Available variables:\n
  * - plugin_id: The ID of the block implementation.\n
  * - label: The configured label of the block if visible.\n
- * - configuration: A list of the block's configuration values.\n
+ * - configuration: A list of the block's configuration values.\n
  *   - label: The configured label for the block.\n
  *   - label_display: The display settings for the label.\n
  *   - provider: The module or other provider that provided this block plugin.\n

/var/www/html/vendor/phpunit/phpunit/src/Framework/Constraint/Equality/IsEqual.php:96
/var/www/html/modules/contrib/twig_ui/tests/src/FunctionalJavascript/TemplateFormTest.php:143
/var/www/html/vendor/phpunit/phpunit/src/Framework/TestResult.php:726

FAILURES!
Tests: 2, Assertions: 29, Failures: 1.

Steps to reproduce

Run tests with PHP 8.1.

Proposed resolution

Debug and fix failing test.

Remaining tasks

Submit patch.

User interface changes

None.

API changes

None.

Data model changes

None.