[PhpUnitBridge] Fix DeprecationErrorHandler with PhpUnit 10

[HypeMC]

Q	A
Branch?	5.4
Bug fix?	yes
New feature?	no
Deprecations?	no
Issues	-
License	MIT

Currently, when using the DeprecationErrorHandler with PhpUnit 10, warnings are ignored, e.g.:

use PHPUnit\Framework\TestCase;

class ExampleTest extends TestCase
{
    public function testFindUniqueTournamentMonths(): void
    {
        $someVar = $nonExistentVar; // $nonExistentVar doesn't exist

        self::assertSame(1, 1);
    }
}

PHPUnit 10.5.20 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.4
Configuration: /app/phpunit.xml.dist

PHP Warning:  Undefined variable $nonExistentVar in /app/tests/ExampleTest.php on line 11

Warning: Undefined variable $nonExistentVar in /app/tests/ExampleTest.php on line 11
.                                                                   1 / 1 (100%)

Time: 00:00.010, Memory: 19.22 MB

OK (1 test, 1 assertion)

The reason I added the closure was to return true, otherwise, the errors would still be displayed, e.g.:

  if ('PHPUnit\Util\ErrorHandler::handleError' === $eh) {
      return $eh;
+ } elseif (ErrorHandler::class === $eh) {
+     return ErrorHandler::instance();
  }

PHPUnit 10.5.20 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.4
Configuration: /app/phpunit.xml.dist

PHP Warning:  Undefined variable $nonExistentVar in /app/tests/ExampleTest.php on line 11

Warning: Undefined variable $nonExistentVar in /app/tests/ExampleTest.php on line 11
W                                                                   1 / 1 (100%)

Time: 00:00.009, Memory: 19.22 MB

OK, but there were issues!
Tests: 1, Assertions: 1, Warnings: 1.

Now, it works as expected:

PHPUnit 10.5.20 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.4
Configuration: /app/phpunit.xml.dist

W                                                                   1 / 1 (100%)

Time: 00:00.008, Memory: 19.22 MB

OK, but there were issues!
Tests: 1, Assertions: 1, Warnings: 1.

[nicolas-grekas]

Thank you @HypeMC.