Fix php 7.4 regression on strtolower to false on ClassLikeNameClassNameImportSkipVoter (#7436)

* Fix php 7.4 regression on strtolower to false on ClassLikeNameClassNameImportSkipVoter

* Fix php 7.4 regression on strtolower to false on ClassLikeNameClassNameImportSkipVoter

Author: samsonasik

rules/CodingStyle/ClassNameImport/ClassNameImportSkipVoter/ClassLikeNameClassNameImportSkipVoter.php

@@ -47,7 +47,7 @@ public function shouldSkip(File $file, FullyQualifiedObjectType $fullyQualifiedO
 
         $shortNameLowered = $fullyQualifiedObjectType->getShortNameLowered();
         $fullyQualifiedObjectTypeNamespace = strtolower(
-            substr($fullyQualifiedObjectType->getClassName(), 0, -strlen($fullyQualifiedObjectType->getShortName()) - 1)
+            substr($fullyQualifiedObjectType->getClassName(), 0, -strlen($fullyQualifiedObjectType->getShortName()) - 1) ?: ''
         );
 
         foreach ($classLikeNames as $classLikeName) {