[release/10.0] Migrate to WiX 5 (#117010)

[PranavSenthilnathan]

Backport of #117010. These are the runtime changes to migrate to WiX 5. This includes updating the WiX 3 source files to WiX 5 in addition to UI and localization updates. It also sets the flag telling arcade dependencies to use WiX 5 instead of WiX 3.

WiX 3 is out of support so we need to move to WiX 5 to ensure we get the latest security updates going forward.

Customer Impact

No expected impact.

Regression

• Yes
• No

Testing

Manually validated by CTI team.

Risk

Medium. This could introduce new issues, but we need to move to WiX 5 so it's better to find and fix bugs in RC2 rather than in GA.

[Copilot]

Pull Request Overview

This PR migrates the .NET runtime installer infrastructure from WiX 4 to WiX 5, which is required for continued MSI generation support. The migration updates package references, configuration files, and localizable content to use the new WiX 5 schema and APIs.

Key changes include:

• Update WiX package references to version 5.0.2
• Migrate WiX XML schemas from v4 to v5 namespaces
• Convert localization files from XML content to value attributes

Reviewed Changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
eng/Versions.props	Adds WiX 5 package version definitions
src/installer/pkg/sfx//Directory.Build.	Configures WiX 5 usage and package references
src/installer/pkg/sfx/installers/host.wxs	Updates WiX schema and improves component structure
src/installer/pkg/sfx/bundle/bundle.thm	Modernizes theme file with WiX 5 schema and improved accessibility
src/installer/pkg/sfx/bundle/theme/*/bundle.wxl	Converts localization format from XML content to value attributes

[jkoritzinsky]

Code changes LGTM

[joeloff]

Please check the localization builds to make sure the new content is available to the vendors. There's a parser change required (already in Arcade).

[PranavSenthilnathan]

Please check the localization builds to make sure the new content is available to the vendors. There's a parser change required (already in Arcade).

There was an automated check-in to the wxl files, so I'm assuming everything is set up correctly:
https://github.com/dotnet/runtime/commits/main/src/installer/pkg/sfx/bundle/theme/1028/bundle.wxl

I don't think that's set up for release/10.0, but we can backport the translations if not.