fix: update tests to use new mcp_authorization field

Updates integration tests to use the new mcp_authorization field
instead of the old method of passing Authorization in mcp_headers.

Changes:
- tests/integration/tool_runtime/test_mcp.py
- tests/integration/inference/test_tools_with_schemas.py
- tests/integration/tool_runtime/test_mcp_json_schema.py (6 occurrences)

All tests now use:
  provider_data = {"mcp_authorization": {uri: AUTH_TOKEN}}

Instead of the old rejected format:
  provider_data = {"mcp_headers": {uri: {"Authorization": f"Bearer {AUTH_TOKEN}"}}}

This aligns with the security architecture that prevents
accidentally leaking inference tokens to MCP servers.

tests/integration/inference/test_tools_with_schemas.py

@@ -193,7 +193,7 @@ class TestMCPToolsInChatCompletion:
             mcp_endpoint=dict(uri=uri),
         )
 
-        provider_data = {"mcp_headers": {uri: {"Authorization": f"Bearer {AUTH_TOKEN}"}}}
+        provider_data = {"mcp_authorization": {uri: AUTH_TOKEN}}  # Token without "Bearer " prefix
         auth_headers = {
             "X-LlamaStack-Provider-Data": json.dumps(provider_data),
         }