[MCP][Dash] Integrate MCP Dashboard via Command Palette

Problem to solve

As of this MR, feat(mcp): Add frontend for MCP dashboard (gitlab-org/editor-extensions/gitlab-lsp!2421 - merged), the MCP dashboard is now available to extensions that want to host it.

Proposal

Implement the MCP dashboard as a command palette command in VSCode.

Further details

Links / references