Changes to endpoints so they allow to only get context and then the exercises as well as tidying up a bit

app/services/impl/third_parties/openai.py

@@ -120,7 +120,7 @@ class OpenAI(ILLMService):
             params["temperature"] = temperature
 
         attempt = 0
-        while attempt < max_retries:
+        while attempt < 3:
             result = await self._client.chat.completions.create(**params)
             result_content = result.choices[0].message.content
             try:
@@ -142,6 +142,7 @@ class OpenAI(ILLMService):
                         "content": (
                             f"Previous response: {result_content}\n"
                             f"JSON format: {json_scheme}"
+                            f"Validation errors: {e}"
                         )
                     }
                 ]