Dependencies: Remove Microsoft.CodeAnalysis.CSharp dependency from Umbraco.Infrastructure

[lauraneto]

The Microsoft.CodeAnalysis.CSharp dependency in the Umbraco.Infrastructure project was only needed for runtime compilation and thus is no longer needed.
It also caused dependency problems with EF Core Design in previous .NET versions, as can be seen in #20421 and #17839. In .NET 10 these issues are no longer present, but if they re-appear we will need to apply a similar fix as in #20474.

I also disabled CPM (Central Package Management) in the Umbraco.Web.UI project, as that can sometimes hide dependency issues consumers might encounter.

[Copilot]

Pull Request Overview

This PR removes the Microsoft.CodeAnalysis.CSharp dependency from the Umbraco.Infrastructure project, which was only needed for runtime compilation and is no longer required. Additionally, Central Package Management (CPM) is disabled for the Umbraco.Web.UI project to prevent dependency issues that consumers might encounter.

Key changes:

• Removed Microsoft.CodeAnalysis.CSharp dependency from Umbraco.Infrastructure
• Disabled CPM in Umbraco.Web.UI project and explicitly specified package versions
• Cleaned up unused CodeAnalysis package references from Central Package Management

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/Umbraco.Infrastructure/Umbraco.Infrastructure.csproj	Removes Microsoft.CodeAnalysis.CSharp package reference
src/Umbraco.Web.UI/Umbraco.Web.UI.csproj	Disables CPM and adds explicit version numbers for EF Core Design and ICU packages
Directory.Packages.props	Removes unused CodeAnalysis package versions from central management

[AndyButland]

Looks good. Have tested a local build and run of Umbraco and don't see any issues.