Set default values in validate_api_proxy_response to include more d…

…etails in error responses to clients

Addresses uncaught exception logged in https://neon-ai.sentry.io/issues/6302853101/events/fefd6b7410644e9bacab910f6349bd00/

neon_hana/mq_service_api.py

@@ -57,6 +57,11 @@ def __init__(self, config: dict):
 
     @staticmethod
     def _validate_api_proxy_response(response: dict, query_params: dict):
+        response.setdefault('content',
+                            {"error": "No response content was received",
+                             "raw_response": response,
+                             "raw_query": query_params})
+        response.setdefault('status_code', 500)
         if response['status_code'] == 200:
             try:
                 resp = json.loads(response['content'])