fix: return theme parts as array in parseThemeName (#122)

Author: Morgy93

src/Service/ThemeCleaner.php

@@ -317,6 +317,6 @@ private function parseThemeName(string $themeCode): ?array
             return null;
         }
 
-        return $themeParts;
+        return [$themeParts[0], $themeParts[1]];
     }
 }