Add `azmcp sql db export` command and unit tests

[achyuth-ms]

What does this PR do?

Add azmcp sql db export command and unit tests

[Any additional context, screenshots, or information that helps reviewers]

GitHub issue number?

[Link to the GitHub issue this PR addresses]

Pre-merge Checklist

• [x] Required for All PRs
  • [x] Read contribution guidelines
  • [x] PR title clearly describes the change
  • [x] Commit history is clean with descriptive messages (cleanup guide)
  • [x] Added comprehensive tests for new/modified functionality
  • [x] 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)
• [x] For MCP tool changes:
  • [ ] One tool per PR: This PR adds or modifies only one MCP tool for faster review cycles
  • [x] Updated servers/Azure.Mcp.Server/README.md and/or servers/Fabric.Mcp.Server/README.md documentation
  • [x] Updated command list in /docs/azmcp-commands.md and/or /docs/fabric-commands.md
  • [x] 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
• [x] Extra steps for Azure MCP Server tool changes:
  • [x] Updated test prompts in /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

[achyuth-ms]

/azp run mcp - pullrequest - live

[azure-pipelines[bot]]

Azure Pipelines will not run the associated pipelines, because the pull request was updated after the run command was issued. Review the pull request again and issue a new run command.

[ericshape]

about the failed pipelines, you could run "dotnet format" in your local's mcp repo and then commit the format updates (i.e. white space)

[joshfree]

Adding Do Not Merge label as we are in a no new features period for the rest of October. Please plan to merge this new feature into main after October

[achyuth-ms]

Address: #493

[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