refactor(Chatbot): make _mask_api_key a static method

- Converted _mask_api_key to a static method for better utility.
- Removed unnecessary comment in main.py regarding pyngrok import.

src/Chatbot.py

@@ -50,7 +50,8 @@ def _model_config(self):
                            self.config.HARM_CATEGORIES]
         return generation_config, safety_settings
 
-    def _mask_api_key(self, key):
+    @staticmethod
+    def _mask_api_key(key):
         if len(key) > 6:
             return key[:-6] + '*' * 6
         return '*' * len(key)

src/main.py

@@ -11,7 +11,6 @@
 import numpy as np
 import uvicorn
 
-# Perbaikan import pyngrok
 from pyngrok import ngrok
 
 logging.disable(logging.CRITICAL)