Tool consolidation for wiki tools (#1423)

This pull request refactors and consolidates the Azure DevOps wiki
toolset to align with the remote MCP server's structure. It replaces
multiple specialized wiki tools with a single dispatcher tool using an
`action` parameter, updates documentation for clarity, and improves
error handling and parameter validation.

**Wiki tool consolidation and refactoring:**
- Consolidated all read-only wiki operations into a single `wiki` tool
that uses an `action` parameter to select between listing wikis, getting
wiki details, listing pages, getting page metadata, and retrieving page
content. The previous individual tools (e.g., `mcp_ado_wiki_list_wikis`,
`mcp_ado_wiki_get_wiki`, etc.) are removed. (`src/tools/wiki.ts`,
`docs/TOOLSET.md`)
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**Documentation updates:**
- Updated the `docs/TOOLSET.md` to reflect the new tool grouping,
parameter structure, and to note alignment with the Azure DevOps remote
MCP server. The documentation now describes the new `action`-based
dispatcher and clarifies which parameters are required for each
operation.
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**Error handling improvements:**
- Centralized and clarified error messages for each wiki action,
ensuring consistent and informative feedback for failed operations.

**Parameter validation and flexibility:**
- Improved validation for required parameters based on the chosen
action, and added support for optional parameters such as `url` for page
content retrieval.
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**Write operation tool renaming:**
- Renamed the create/update wiki page tool to `wiki_upsert_page` for
consistency with the new naming scheme.
[[1]](diffhunk://#diff-b17fb169ab8df3740ad297819df82b07c47565474ef0a50c23d3f63c42ed2da0L12-L96)
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These changes simplify the codebase, make the API more intuitive, and
ensure the toolset is consistent with Azure DevOps standards.

## GitHub issue number
N/A

## **Associated Risks**

Changing the signature of tools in wiki

## ✅ **PR Checklist**

- [x] **I have read the [contribution
guidelines](https://github.com/microsoft/azure-devops-mcp/blob/main/CONTRIBUTING.md)**
- [x] **I have read the [code of conduct
guidelines](https://github.com/microsoft/azure-devops-mcp/blob/main/CODE_OF_CONDUCT.md)**
- [x] Title of the pull request is clear and informative.
- [x] 👌 Code hygiene
- [x] 🔭 Telemetry added, updated, or N/A
- [x] 📄 Documentation added, updated, or N/A
- [x] 🛡️ Automated tests added, or N/A

## 🧪 **How did you test it?**

manually testing all of the wiki tools and made sure automated tests are
updated