[installer] Fix wix warnings introduced by MeasureTool

[stefansjfw]

Summary of the Pull Request

Not the nicest change there is but I'd prefer this rather than disabling warnings.

PR Checklist

• Closes: Screen measuring tool #863
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

[yuyoyuppe]

LGTM!