[5.x] Fix collection title_format when using translations (#11248)

src/Entries/Entry.php

@@ -1008,7 +1008,7 @@ public function autoGeneratedTitle()
 
         // Since the slug is generated from the title, we'll avoid augmenting
         // the slug which could result in an infinite loop in some cases.
-        $title = $this->withLocale($this->site()->locale(), fn () => (string) Antlers::parse($format, $this->augmented()->except('slug')->all()));
+        $title = $this->withLocale($this->site()->lang(), fn () => (string) Antlers::parse($format, $this->augmented()->except('slug')->all()));
 
         return trim($title);
     }