feat(logging): Add debug log for empty OpenAI responses

Introduces logging for cases where OpenAI's API returns an empty response, ensuring that such occurrences are captured for debugging purposes. This change enhances visibility into the interaction with OpenAI's endpoint, facilitating easier identification and resolution of issues where empty responses are received, potentially indicating API limitations, network issues, or unexpected behavior from the AI model.

src/gptbot/classes/openai.py

@@ -493,6 +493,9 @@ class OpenAI:
                 model=original_model,
             )
 
+        if not result_text:
+            self.logger.log(f"Received an empty response from the OpenAI endpoint.", "debug")
+
         try:
             tokens_used = response.usage.total_tokens
         except: