Normalize outbound MCP tool arguments

[Bionic711]

Motivation & Context

Outbound MCP tools that receive parameters through Semantic Kernel can arrive at SimpleChat as a single kwargs wrapper. Standards-compliant MCP servers expect tool parameters as top-level fields inside the tools/call arguments object, so wrapped payloads such as { "kwargs": { "type": "..." } } can make required fields invisible to servers such as Splunk MCP. This fixes issue #1163 so parameterized outbound MCP tools receive the expected argument shape while no-parameter tools and legitimate kwargs fields remain safe.

Description & Review Guide

What are the major changes?

• Added schema-aware MCP tool-call argument normalization in functions_mcp_operations.py.
• Wired normalization into McpPlugin.call_tool(...) before validation and invocation.
• Added factory-level defense-in-depth in McpPluginFactory.call_tool_from_config(...) for direct factory callers with cached tool metadata.
• Added functional_tests/test_mcp_tool_argument_normalization.py covering plugin and factory paths, direct top-level args, wrapped kwargs, legitimate kwargs schemas, and no-argument calls.
• Bumped config.py to 0.250.127 and added release notes.

What is the impact of these changes?

• Parameterized outbound MCP tools now forward required fields such as type at the top level expected by MCP servers.
• Tools that explicitly define a real top-level kwargs property continue to receive that wrapper unchanged.
• Factory calls without cached tool metadata stay conservative and do not guess/unwrap unknown tool payloads.

What do you want reviewers to focus on?

• Human reviewers: please focus on the schema-aware unwrap conditions and whether the factory-level conservative behavior is the right compatibility tradeoff. Automated/AI reviewers should review the full change.

Local validation completed before opening this draft:

• python functional_tests\test_mcp_tool_argument_normalization.py
• python functional_tests\test_mcp_action_manifest_workflow.py
• python functional_tests\test_mcp_phase2_probe_metadata.py
• python functional_tests\test_mcp_destination_governance_and_preconfigurations.py
• python functional_tests\test_local_mcp_server.py
• python functional_tests\test_app_version_assertion_guardrails.py
• python -m py_compile application\single_app\config.py application\single_app\functions_mcp_operations.py application\single_app\semantic_kernel_plugins\mcp_plugin.py application\single_app\semantic_kernel_plugins\mcp_plugin_factory.py functional_tests\test_mcp_tool_argument_normalization.py
• python scripts\check_xss_sinks.py --full-file application\single_app\config.py application\single_app\functions_mcp_operations.py application\single_app\semantic_kernel_plugins\mcp_plugin.py application\single_app\semantic_kernel_plugins\mcp_plugin_factory.py
• python scripts\check_broken_access_control.py --full-file application\single_app\config.py application\single_app\functions_mcp_operations.py application\single_app\semantic_kernel_plugins\mcp_plugin.py application\single_app\semantic_kernel_plugins\mcp_plugin_factory.py
• git diff --check

Related Issue

Fixes #1163

Contribution Checklist

• This is not a breaking change.
• I added or updated tests to cover the change.
• I updated release notes for the user-facing bug fix.
• I ran targeted local validation for the changed MCP surfaces.