Add `azmcp sql server conn-policy show` and unit tests

[ericshape]

What does this PR do?

Add azmcp sql server conn-policy show and unit tests

GitHub issue number?

[Link to the GitHub issue this PR addresses]

Pre-merge Checklist

• [ ] Required for All PRs
  • [ ] Read contribution guidelines
  • [ ] PR title clearly describes the change
  • [ ] Commit history is clean with descriptive messages (cleanup guide)
  • [ ] Added comprehensive tests for new/modified functionality
  • [ ] Updated servers/Azure.Mcp.Server/CHANGELOG.md and/or servers/Fabric.Mcp.Server/CHANGELOG.md for product changes (features, bug fixes, UI/UX, updated dependencies)
• [ ] For MCP tool changes:
  • [ ] One tool per PR: This PR adds or modifies only one MCP tool for faster review cycles
  • [ ] Updated servers/Azure.Mcp.Server/README.md and/or servers/Fabric.Mcp.Server/README.md documentation
  • [ ] Validate README.md changes using script at eng/scripts/Process-PackageReadMe.ps1. See Package README
  • [ ] Updated command list in /servers/Azure.Mcp.Server/docs/azmcp-commands.md and/or /docs/fabric-commands.md
  • [ ] For new or modified tool descriptions, ran ToolDescriptionEvaluator and obtained a score of 0.4 or more and a top 3 ranking for all related test prompts
  • [ ] For new tools associated with Azure services or publicly available tools/APIs/products, add URL to documentation in the PR description
• [ ] Extra steps for Azure MCP Server tool changes:
  • [ ] Updated test prompts in /servers/Azure.Mcp.Server/docs/e2eTestPrompts.md
  • [ ] 👉 For Community (non-Microsoft team member) PRs:
    • [ ] Security review: Reviewed code for security vulnerabilities, malicious code, or suspicious activities before running tests (crypto mining, spam, data exfiltration, etc.)
    • [ ] Manual tests run: added comment /azp run mcp - pullrequest - live to run Live Test Pipeline

[joshfree]

Let's hold new tools until main opens up for 2.0-beta

[fanyang-mono]

Make sure to update consolidated-tools.json](https://github.com/microsoft/mcp/blob/main/core/Azure.Mcp.Core/src/Areas/Server/Resources/consolidated-tools.json). You can find instructions in https://github.com/microsoft/mcp/blob/main/CONTRIBUTING.md