Update client_v2.py with handling JSON Decode error

## What

This PR improves error handling in the `LLMWhispererClientV2.whisper_status` function.  
The update ensures empty or non-JSON API responses are handled gracefully: errors are now logged using `self.logger` and clear, actionable exceptions are raised, preventing uninformative or misleading `JSONDecodeError` stack traces.

## Why

Previously, when the API failed and returned an empty or malformed response, the client attempted to parse it as JSON, resulting in cryptic errors and poor diagnostics for downstream consumers.  
This change makes error messages clear and actionable, improving maintainability and debuggability for both developers and users.

## How

- Adds a defensive check for empty (`None` or blank) response bodies.
- Wraps `json.loads(response.text)` in a try/except; logs errors and response content with `self.logger`.
- Raises `LLMWhispererClientException` using the correct constructor signature (`value, status_code`).
- All raised exceptions now include the original status code and a clear error message.

## Relevant Docs

N/A

## Related Issues or PRs

- Fixes: LW-158

## Notes on Testing

- Manually simulated API failures with empty and non-JSON responses to verify clear logging and correct exception behavior.
- Ensured that all existing integration tests for client error handling continue to pass.

## Checklist

I have read and understood the [Contribution Guidelines]().

Signed-off-by: ali <[email protected]>

Author: muhammad-ali-e

src/unstract/llmwhisperer/client_v2.py

@@ -446,9 +446,15 @@ def whisper_status(self, whisper_hash: str) -> Any:
         s = requests.Session()
         response = s.send(prepared, timeout=self.api_timeout)
         if response.status_code != 200:
-            err = json.loads(response.text)
-            err["status_code"] = response.status_code
-            raise LLMWhispererClientException(err)
+            if not (response.text or "").strip():
+                self.logger.error(f"Empty response body from API, status code: {response.status_code}")
+                raise LLMWhispererClientException("Empty response body from API", response.status_code)
+            try:
+                err = json.loads(response.text)
+            except json.JSONDecodeError as e:
+                self.logger.error(f"JSON decode error: {e}; Response text: {response.text!r}")
+                raise LLMWhispererClientException(f"Non-JSON response: {response.text}", response.status_code) from e
+            raise LLMWhispererClientException(err, response.status_code)
         message = json.loads(response.text)
         message["status_code"] = response.status_code
         return message