Exclude Obo roots when building in trim mode given the AOT violations in Obo apis

[anuchandy]

…

What does this PR do?

The Azure MCP Server is distributed as a fully trimmed, self-contained executable. The ongoing work for On-Behalf-Of (OBO) authentication currently leverages the Microsoft.Identity.Web package, whose OBO implementation relies on non–AOT-compatible APIs - specifically ConfigurationBinder.Bind, which is marked with RequiresUnreferencedCodeAttribute. The issue is being tracked here: AzureAD/microsoft-identity-web#3576.

To unblock the CI pipeline, this PR temporarily excludes the OBO code path when building in Trimmed mode. In other words, running below command (that CI uses) produces a single-file trimmed executable without the OBO APIs.

./eng/scripts/Build-Code.ps1 -SelfContained -Trimmed -SingleFile -Server "Azure.Mcp.Server"

For local development and testing, developers can still build a non-trimmed version of azmcp that includes OBO support by running:

./eng/scripts/Build-Code.ps1 -SelfContained -SingleFile -Server "Azure.Mcp.Server"

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:
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  • 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
  • Run .\eng\scripts\Update-AzCommandsMetadata.ps1 to update tool metadata in azmcp-commands.md (required for CI)
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  • 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
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    • Manual tests run: added comment /azp run mcp - pullrequest - live to run Live Test Pipeline

[anuchandy]

closing this given we're going to include remote in untrimmed build for docker, and for all other distributions it is trimmed, which is addressed in #1008