fix: improve empty text validation in recognize_locale method

Author: maxprilutskiy

src/lingodotdev/engine.py

@@ -366,7 +366,7 @@ def recognize_locale(self, text: str) -> str:
         Returns:
             A locale code (e.g., 'en', 'es', 'fr')
         """
-        if not text.strip():
+        if not text or not text.strip():
             raise ValueError("Text cannot be empty")
 
         url = urljoin(self.config.api_url, "/recognize")