Add missing Scale qualifier default value information and warnings to build-resources-into-app-package.md

[Copilot]

The documentation for Option 2 in "Build resources into your app package" was missing critical information about how <AppxDefaultResourceQualifiers> overrides ALL default qualifier values, not just the ones specified. This caused users to lose built-in defaults like Scale=200, resulting in missing scaled images in packaged apps.

Problem

When users followed the documentation to add:

<AppxDefaultResourceQualifiers>Language=en;es;fr</AppxDefaultResourceQualifiers>

They would lose the built-in Scale=200 default and other qualifier defaults, causing their apps to be missing 200% scale images and other resources.

Solution

• Added Important warning explaining that <AppxDefaultResourceQualifiers> replaces ALL defaults
• Updated examples to show the complete syntax including Scale=200 and all other default qualifiers
• Provided both options: Complete syntax for preserving all defaults, and shorter syntax with clear warnings about consequences
• Enhanced Option 1 consistency by showing the complete qualifier list in priconfig.default.xml examples
• Added cross-references to the complete documentation for default values

The changes directly address the specific issue of missing scaled images while providing comprehensive guidance for all qualifier defaults.

Fixes #4344.

---

💬 Share your feedback on Copilot coding agent for the chance to win a $200 gift card! Click here to start the survey.

[Copilot]

Copilot wasn't able to review any files in this pull request.

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[learn-build-service-prod]

Learn Build status updates of commit fcc0c92:

⚠️ Validation status: warnings

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

[learn-build-service-prod]

Learn Build status updates of commit 63663ba:

✅ Validation status: passed

File	Status	Preview URL	Details
uwp/app-resources/build-resources-into-app-package.md	✅Succeeded

For more details, please refer to the build report.

[learn-build-service-prod]

Learn Build status updates of commit 090aa24:

✅ Validation status: passed

File	Status	Preview URL	Details
uwp/app-resources/build-resources-into-app-package.md	✅Succeeded

For more details, please refer to the build report.