Python: improve misc-integration test robustness (#5295)

* Python: use local MCP server for hosted tools test and broaden image assertion

The hosted tools integration test was hitting rate limits on the external
learn.microsoft.com MCP server, causing persistent failures that retries
couldn't recover from. Switch to the local MCP server already spun up in
CI via LOCAL_MCP_URL, skipping when the env var isn't set.

Also broaden the image description assertion to accept common synonyms
(cottage, mansion, villa, etc.) instead of just "house", since the model
legitimately uses varied vocabulary for the same image.

* Address review feedback: validate LOCAL_MCP_URL scheme and use word boundaries

- Skip hosted tools test when LOCAL_MCP_URL lacks http/https scheme,
  matching the pattern used in test_mcp.py.
- Use regex word boundaries for image assertion to avoid false matches
  like "villain" matching "villa".

python/packages/anthropic/tests/test_anthropic_client.py

@@ -1,5 +1,6 @@
 # Copyright (c) Microsoft. All rights reserved.
 import os
+import re
 from pathlib import Path
 from typing import Annotated, Any
 from unittest.mock import MagicMock, patch
@@ -1503,6 +1504,10 @@ async def test_anthropic_client_integration_function_calling() -> None:
 @skip_if_anthropic_integration_tests_disabled
 async def test_anthropic_client_integration_hosted_tools() -> None:
     """Integration test for hosted tools."""
+    local_mcp_url = os.environ.get("LOCAL_MCP_URL", "")
+    if not local_mcp_url or not local_mcp_url.startswith(("http://", "https://")):
+        pytest.skip("LOCAL_MCP_URL not set or not an HTTP URL; skipping hosted tools test")
+
     client = AnthropicClient()
 
     messages = [Message(role="user", contents=["What tools do you have available?"])]
@@ -1510,8 +1515,8 @@ async def test_anthropic_client_integration_hosted_tools() -> None:
         AnthropicClient.get_web_search_tool(),
         AnthropicClient.get_code_interpreter_tool(),
         AnthropicClient.get_mcp_tool(
-            name="example-mcp",
-            url="https://learn.microsoft.com/api/mcp",
+            name="local-mcp",
+            url=local_mcp_url,
         ),
     ]
 
@@ -1607,7 +1612,8 @@ async def test_anthropic_client_integration_images() -> None:
 
     assert response is not None
     assert response.messages[0].text is not None
-    assert "house" in response.messages[0].text.lower()
+    text = response.messages[0].text.lower()
+    assert re.search(r"\b(house|home|building|cottage|mansion|villa)\b", text)
 
 
 # Response Format Tests