Update CI workflows to use Presidio.slnx solution

[KSemenenko]

Summary

• update the CI workflow to restore, build, test, and format against the Presidio.slnx solution
• update the release workflow to pack and publish using Presidio.slnx so GitHub Actions no longer looks for the missing Presidio.sln file

Testing

• dotnet format Presidio.slnx --verify-no-changes (fails: existing xUnit1039 analyzer errors in analyzer test data definitions)
• dotnet test Presidio.slnx --configuration Release (fails: existing xUnit1039 analyzer errors in analyzer test data definitions)

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Codex Task

[Copilot]

Pull Request Overview

This PR updates the GitHub Actions workflow files to use the new .slnx solution file format instead of the legacy .sln format. The repository has already migrated to using Presidio.slnx (an XML-based solution format introduced in Visual Studio 2022 version 17.10), and this change updates the CI/CD pipelines to reference the correct file.

• Updates all dotnet CLI commands in workflows to reference Presidio.slnx
• Ensures consistency between the repository structure and the build automation

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
.github/workflows/ci.yml	Updates all dotnet commands (restore, format, build, test) to use Presidio.slnx instead of Presidio.sln
.github/workflows/release.yml	Updates all dotnet commands (restore, build, test, pack) to use Presidio.slnx instead of Presidio.sln