Fix: Enable max_retries Parameter in ChatMistralAI Class (#30448)

**partners: Enable max_retries in ChatMistralAI**

**Description**

- This pull request reactivates the retry logic in the
completion_with_retry method of the ChatMistralAI class, restoring the
intended functionality of the previously ineffective max_retries
parameter. New unit test that mocks failed/successful retry calls and an
integration test to confirm end-to-end functionality.

**Issue**
- Closes #30362

**Dependencies**
- No additional dependencies required

Co-authored-by: andrasfe <andrasf94@gmail.com>

libs/partners/mistralai/tests/integration_tests/test_chat_models.py

@@ -1,9 +1,12 @@
 """Test ChatMistral chat model."""
 
 import json
+import logging
+import time
 from typing import Any, Optional
 
 import pytest
+from httpx import ReadTimeout
 from langchain_core.messages import (
     AIMessage,
     AIMessageChunk,
@@ -301,3 +304,39 @@ def test_streaming_tool_call() -> None:
         acc = chunk if acc is None else acc + chunk
     assert acc.content != ""
     assert "tool_calls" not in acc.additional_kwargs
+
+
+def test_retry_parameters(caplog: pytest.LogCaptureFixture) -> None:
+    """Test that retry parameters are honored in ChatMistralAI."""
+    # Create a model with intentionally short timeout and multiple retries
+    mistral = ChatMistralAI(
+        timeout=1,  # Very short timeout to trigger timeouts
+        max_retries=3,  # Should retry 3 times
+    )
+
+    # Simple test input that should take longer than 1 second to process
+    test_input = "Write a 2 sentence story about a cat"
+
+    # Measure start time
+    t0 = time.time()
+
+    try:
+        # Try to get a response
+        response = mistral.invoke(test_input)
+
+        # If successful, validate the response
+        elapsed_time = time.time() - t0
+        logging.info(f"Request succeeded in {elapsed_time:.2f} seconds")
+        # Check that we got a valid response
+        assert response.content
+        assert isinstance(response.content, str)
+        assert "cat" in response.content.lower()
+
+    except ReadTimeout:
+        elapsed_time = time.time() - t0
+        logging.info(f"Request timed out after {elapsed_time:.2f} seconds")
+        assert elapsed_time >= 3.0
+        pytest.skip("Test timed out as expected with short timeout")
+    except Exception as e:
+        logging.error(f"Unexpected exception: {e}")
+        raise