[DeadCode] IsClassMethodUsedAnalyzer needs to use Scope from Class_ level (#6910)

Author: samsonasik

rules/DeadCode/Rector/ClassMethod/RemoveEmptyClassMethodRector.php

@@ -131,7 +131,7 @@ private function shouldSkipNonFinalNonPrivateClassMethod(Class_ $class, ClassMet
     private function shouldSkipClassMethod(Class_ $class, ClassMethod $classMethod): bool
     {
         // is method called somewhere else in the class?
-        $scope = ScopeFetcher::fetch($classMethod);
+        $scope = ScopeFetcher::fetch($class);
         if ($this->isClassMethodUsedAnalyzer->isClassMethodUsed($class, $classMethod, $scope)) {
             return true;
         }