load chatbot: Check for empty chatbot ID

tabs/chat.py

@@ -9,6 +9,13 @@ logger = logging.getLogger(__name__)
 
 def load_chatbot(chatbot_id):
     logger.info(f"Attempting to load chatbot with ID: {chatbot_id}")
+    if chatbot_id is None or chatbot_id == "":
+        return (
+            gr.update(value="# Chatbot\n\nWillkommen beim Chatbot"),
+            gr.update(value="", visible=True),
+            gr.update(value=""),
+            gr.update(value="Bitte gib eine Chatbot-ID ein.")
+        )
     try:
         chatbot = get_chatbot(chatbot_id)
     except Exception as e: