[simonrozsival]

Context: #13490

#13490 removed Xamarin.Android.Bindings.Documentation.targets and two of the three uses of the <UnzipToFolder/> task. The only remaining use is in _CreateUniversalApkFromBundle. That target extracts universal.apk from the bundletool .apks set ($(_UniversalApkSetIntermediate)) and renames it to $(OutDir)$(_AndroidPackage)-Signed.apk through the %(DestinationFileName) metadata.

MSBuild's built-in <Unzip/> and <Copy/> tasks can do the same job, so the custom task is no longer needed:

• <Unzip Include="universal.apk"/> extracts the entry into a new intermediate directory, $(IntermediateOutputPath)android\bin\universal-apk\. The built-in Unzip task rejects archive entries that would land outside DestinationFolder, which replaces the Files.GetArchiveExtractionPath() checks that UnzipToFolder did.
• <Copy/> then writes the file to $(OutDir)$(_AndroidPackage)-Signed.apk.
• SkipUnchangedFiles="false" is set on <Unzip/>. bundletool writes universal.apk with a fixed ZIP timestamp, so the default size/timestamp check could skip a changed file. For the same reason, the existing <Touch/> is kept.
• The extracted intermediate file is added to @(FileWrites).

Delete UnzipToFolder.cs and its <UsingTask/>. The task had no tests. Files.ExtractAll() and Files.GetArchiveExtractionPath() stay, because ResolveLibraryProjectImports, ExtractJarsFromAar, and FilesTests still use them.

This PR is stacked on #13490.

Testing: Not run locally. Builds and tests were skipped for this batch to save local disk space, so CI validates the change. In particular, CI needs to confirm that AndroidPackageFormat=aab builds that also produce an APK still create -Signed.apk, and that incremental builds still behave correctly.

[Copilot]

🟢 Approval recommended

No active review issues are reported for the MSBuild task cleanup.

No open issues 🎉

What changed in this PR

Replaces the last use of the custom UnzipToFolder task with built-in MSBuild tasks, completing cleanup after #13490 while preserving universal APK output naming.

Changes:

• Extracts universal.apk into an intermediate directory, then copies it to the signed APK output path.
• Forces extraction despite fixed ZIP timestamps, retains the output timestamp update, and tracks the intermediate file for cleanup.
• Removes the unused custom task and its registration.

Local validation was not run, per the PR description.

File	Description
src/​Xamarin.Android.Build.Tasks/​Xamarin.Android.Common.targets	Uses built-in Unzip and Copy for universal APK extraction and removes the custom task registration.
src/​Xamarin.Android.Build.Tasks/​Tasks/​UnzipToFolder.cs	Deletes the now-unused extraction task.

_{Review effort: Balanced}