reverted removing getter which is still relied upon

Author: konradoboza

src/lib/Form/Data/Content/Translation/MainTranslationUpdateData.php

@@ -30,4 +30,9 @@ public function setLanguageCode(?string $languageCode = null): void
     {
         $this->languageCode = $languageCode;
     }
+
+    public function getLanguageCode(): ?string
+    {
+        return $this->languageCode;
+    }
 }