Remove redundant rule test for bug-13510

The NSRT test already covers the type inference regression. The separate
rule test is unnecessary.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Properties/TypesAssignedToPropertiesRuleTest.php

@@ -1071,9 +1071,4 @@ public function testBug10749(): void
 		$this->analyse([__DIR__ . '/data/bug-10749.php'], []);
 	}
 
-	public function testBug13510(): void
-	{
-		$this->analyse([__DIR__ . '/data/bug-13510.php'], []);
-	}
-
 }