Amazon Q VScode plugin - MCP server list didn't sync up with mcp.json

## Problem

## Steps to reproduce the issue

1. after remove some MCP server at ~/.aws/amazonq/mcp.json
2. MCP server still shown the old list of MCP server (it didn't reflect the updated MCP server as ~/.aws/amazonq/mcp.json)

## Expected behavior

The list of MCP server appear on Amazon Q VScode Plugin, it's supposed to in-sync with mcp.json file.

## System details (run `AWS: About` and/or `Amazon Q: About`)

- OS: Mac
- Visual Studio Code version: version 1.104
- AWS Toolkit version:
- Amazon Q version: 1.97.0

Reproduce the issue in the Amazon Q VS Code extension after removing a server from ~/.aws/amazonq/mcp.json. Trace how the extension loads and refreshes the MCP server list; done means removed servers no longer appear after the configuration file changes.

Written by the indexing model from the issue text.