Tests: Fix array alignment in icon collection tests.

Address the PHPCS `WordPress.Arrays.MultipleStatementAlignment` warning
by aligning the `label` key with the sibling `bogus` key in
`test_register_rejects_unknown_property`.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: t-hamano

tests/phpunit/tests/icons/wpIconCollectionsRegistry.php

@@ -111,7 +111,7 @@ public function test_register_rejects_unknown_property() {
 		$result = $this->collections->register(
 			'my-collection',
 			array(
-				'label'   => 'A',
+				'label' => 'A',
 				'bogus' => 'nope',
 			)
 		);