fix(doctrine): keep zero-backed enum filter values

[ousamabenyounes]

Fix #8475

BackedEnumFilter normalized integer-backed enum query values before checking whether any valid values remained. The default array_filter() callback also removed the valid integer value 0, causing the filter to be silently skipped.

This keeps every normalized value except null, which is the sentinel returned for invalid enum values. A regression test covers zero and confirms negative values remain supported.

Test verification (RED → GREEN)

On unmodified 4.3, the new test failed for the zero-backed case:

Failed asserting that two strings are identical.
-'SELECT o FROM ApiPlatform\Doctrine\Orm\Tests\Fixtures\Entity\IntegerBackedEnumDummy o WHERE o.value = :value_p1'
+'SELECT o FROM ApiPlatform\Doctrine\Orm\Tests\Fixtures\Entity\IntegerBackedEnumDummy o'
Tests: 2, Assertions: 2, Failures: 1.

With the fix:

OK (2 tests, 2 assertions)

Full local suite

Command: ./run-ci.sh (Doctrine ORM BackedEnumFilterTest on PHP 8.4 and PHP 8.5, matching the affected component CI job).

Result: same-or-better than the upstream baseline, with no new failures, skips, ignores, or errors.

Upstream 4.3: OK (7 tests, 9 assertions)
PHP 8.4: OK (9 tests, 11 assertions)
PHP 8.5: OK (9 tests, 11 assertions)
PHP CS Fixer 3.93.1: 0 of 4 files can be fixed
Changed production lines: 100% covered (1/1)

[soyuka]

thanks!